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PCOM: Anatomy 2 - midterm set - digestive, blood, and cardiovascular systems

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the three layers of the blood vessel walls, internal to external
tunica intima, tunica media, tunica externa
three layers of the tunica intima, internal to external
endothelium, sub-endothelial layer, internal elastic lamina
function of the tunica intima
reduces friction between the vessel walls and the blood
layer of the tunica intima that is not found in veins
internal elastic lamina
the basal membrane of the blood vessels
the sub-endothelial layer
function of the internal elastic lamina
elasticity for arteries due to arterial pressure (high pressure system)
composition of the tunica media
smooth and elastic muscles and the external elastic lamina
differences in the tunica media in arteries and veins
thinner in veins as it is a low pressure system
two layers of the tunica media in arteries
muscle layer and the external elastic lamina
function of the tunica media
controls vasodilation and vasoconstriction
composition of the tunica externa
collagen fibers
function of the tunica externa
protects, reenforces, and anchors the vessel to surrounding structures
feature of vessel structure found in veins only
internal, one way venous valves that are covered in endothelium
function of the venous valves
to prevent back flow of blood as it returns to the heart - found mostly in the extremities
how blood returns to the heart against gravity
the muscles of the leg pump it up as constricting occurs during use (e.g. walking)
how blood form the abdominopelvic region returns to the heart
the respiratory pump - contraction of the diaphragm creates high pressure in the lower region and low pressure in the upper region, causing blood to be drawn upward
the largest arteries as they lead away from the heart
elastic or conducting arteries
physical characteristic of conducting arteries allowing them to withstand changes in arterial pressure due to the heart action
contain large amounts of elastin, creating elasticity
second level of arteries
muscular or distributing arteries
function of muscular or distributing arteries
deliver blood to specific organs and very active in vasoconstriction
important physical characteristic of muscular or distributing arteries
they contain the largest tunica media of all arteries due to greater muscle content for vasoconstriction
smallest arteries
arterioles
function of the arterioles
regulate blood flow into the capillary beds through vasoconstriction and vasodilation
important physical characteristic of arterioles
the muscle layer of the tunica media is made of smooth muscle only
physical characteristic of the capillaries
they are the smallest vessels
function of the capillaries
they allow the exchange of substances between the vessels and the interstitial fluid
continuous capillaries
contain no muscle, the capillary wall is one cell thick with a basement membrane, and are the least permeable and most common capillary; still allow the passage of fluids and small solutes
fenestrated capillaries
contain fenestrations (small pores) and are more permeable than continuous capillaries and are found in specialized locations like the kidneys and small intestine
sinusoidal capillaries
the most permeable capillaries allowing large molecules to pass through; found in the liver, spleen and bone marrow
where the smallest capillaries are found
in the spleen - sinusoidal
structure at the end of the arterial circulation
capillary beds
structure of the capillary beds
microcirculatory network with a vascular shunt and the true capillaries that act as exchange vessels
structure at the entry point for the capillary beds
pre-capillary sphincter
function of the pre-capillary sphincter
regulates the flow of blood through the capillary bed
structure of the pre-capillary sphincter
a cuff of smooth muscle surrounding each capillary at the metarteriole
blood flow when the pre-capillary sphincter is open
blood flows into the capillary bed allowing the plasma to leave the blood into the interstitial spaces with nutrients, etc for the tissues/cells they supply
blood flow when the pre-capillary sphincters are closed
blood passes through the vascular shunt, bypassing the capillary bed without release plasma and its solutes
where the plasma released into the interstitial fluids returns to the blood
in the venous side of the capillary bed - the beginning of venous system
percentage of plasma that is not returned to the blood by capillary re-uptake
1%
where the capillaries converge
venules - allow fluid and WBCs to move easily between the blood and tissues
what venules form as they converge
veins
physical characteristics of veins
thin walled with relatively large lumens
additional term for small and large veins
capacitance vessels
function of veins as capacitance vessels
store blood - 65% of the blood in the body is in the venous system at any given time
venous response when blood pressure drops
vasoconstriction - increases the blood volume in the arterial system
percentage of blood in systemic circulation at any given time
84%
vascular anastomoses
where vascular channels unite forming alternative blood pathways to allow blood supply and drainage from an area even if one channel is blocked
blood pressure
measured in arteries - the force per unit area exerted by the blood on the blood walls expressed in millimeters of mercury
effect of High Blood Pressure
damages the endothelium of the vessels leading to atherosclerosis
how blood pressure results
the resistance of the blood during the pumping action of t heart
blood pressure levels throughout the systemic circuit
highest in the aorta, decreasing throughout the pathway until is reaches 0 in the right atrium
cardiac output
the amount of blood ejected from the ventricle each minute CO = SV (stroke volume) x HR (heart rate)
stroke volume
the amount of blood ejected by the ventricle on each contraction
what arterial Blood pressure signifies
how much the arteries close to the heart can be stretched (compliance or distensibility) and the volume of blood forced into them at any given time
systolic pressure
the peak pressure created when the left ventricle contracts forcing blood into the aorta (normally about 120mm Hg)
diastolic pressure
the pressure created when back flow into the ventricles is prevented by the semilunar valves (normally about 70-80 mm Hg)
characteristics of where arteries run
deep and are well protected
characteristics of where veins run
both deep (parallel to the arteries) and superficial (just under the skin
number of terminal systemic arteries
one - the aorta
number of terminal systemic veins
two - inferior and superior vena cava
three parts of the aorta
ascending aorta, arch of the aorta, thoracic aorta
the 4 paired arteries of the head and neck
costocervical trunk, thyrocervical trunk, vertebral artery, common carotid artery
from where the left common carotid artery arises
from the aortic arch
from where the right common carotid arises
from the brachiocephalic trunk as it branches from the aortic arch
two branches of the common carotid
the external and internal
area the internal carotid supplies
major supplier of blood to the brain
area the external carotid supplies
the scalp, face, larynx and some of the thyroid
from where the vertebral arteries arise
subclavian artery, the first and most medial branch
area the vertebral artery supplies
passes through the transverse processes of the cervical spine and supplies the brain
from where the thyrocervical artery arises
subclavian artery, lateral to the vertebral arteries
area the thyrocervical trunk supplies
thyroid gland and portions of the cervical spine
from where the costocervical artery arises
subclavian artery, lateral to the thyrocervical arteries
area the costocervical artery supplies
deep neck muscles
the three branches of the aortic arch from right to left
the brachiocephalic trunk, the left common carotid, the left subclavian
the two branches of the brachiocephalic trunk medial to lateral
the right common carotid, the right subclavian
area supplied by the subclavian arteries
the upper extremities
pathway of the subclavian arteries
becomes the axillary artery at the armpit, the brachial artery at the elbow and the radial and ulnar arteries at the wrist
from where the left and right coronary arteries arise
the ascending aorta
artery that supplies the abdomen
the abdominal aorta
from the where the abdominal aorta arises
from the thoracic aorta as it passes through the aortic hiatus in the diaphragm
most proximal artery that supplies the lever, stomach and spleen
celiac trunk
artery that supplies intestines, rectum and tissues
superior and inferior mesenteric arteries
from where the mesenteric arteries arise
the abdominal aorta
artery that supplies the kidneys
the renal artery
from where the renal arteries arise
between the superior and inferior mesenteric arteries off the abdominal aorta
arteries that supply the pelvis and lower extremities
the common iliac arteries
from where the common iliac arteries arise
the abdominal artery bifurcates at around the iliac crest/L-4 level, forming the right and left common iliac arteries
how blood supply moves to the pelvis
the common iliac bifurcates and the pelvis and pelvic organs are supplied by the internal iliac artery
how blood supply moves to the lower extremities
the common iliac bifurcates and the external iliac artery supplies the lower extermities
pathway of the external iliac arteries
becomes the femoral artery in the thigh, has multiple branches at the knee
area from which blood drains to the superior vena cava
head, neck, upper extermities
area from which blood drains to the inferior vena cava
the trunk and lower extremities
area from which blood drains to the coronary sinus
the heart
three pairs of veins to which blood drains from the head and neck
external jugular, vertebral, and internal jugular
area from which blood drains to the external jugular
scalp and face
area from which blood drains to the vertebral veins
the brain
area from which blood drains to the internal jugular
the brain
the area to which the external vein drains
the subclavian vein
area to which the subclavian, vertebral and internal jugular drain
the brachiocephalic branch bilaterally
area to which the brachiocephalic veins drain
the merge and become the superior vena cava
pathway by which the blood of the thoracic wall and tissues are drained
the accessory hemi-azygos veins to the hemi-azygos veins, which merge to the azygos vein which drains to the superior vena cava
pathway by which the abdominal viscera and abdominal walls drain
through the portal system - the splenic vein drains the spleen and merges with the superior mesenteric vein to become the hepatic portal vein which transports blood to the two lobes of the liver for the storage of unused nutrients which then drains the blood to the inferior vena cava via the Right and left hepatic veins
to where the inferior mesenteric circulation drains
to the splenic vein
pathway by which the blood drains from the pelvis and pelvic organs
via the internal iliac vein which merges with the external iliac vein to form the common iliac vein to the inferior vena cava
pathway by which the blood drains from the lower extremities
lower limbs via several veins to the femoral vein in th thigh to the external iliac vein which merges with the internal iliac vein to form the common iliac vein which feed to the inferior vena cava
function of the lymph system
takes up the 1% of the plasma that is not reabsorbed by the venus capillaries in the capillary beds during circulation and cleans it
flow of the lymphatic system
one way to the heart
beginning of the lymph system
lymph capillaries between the tissue cells and the blood capillaries in the loose CT - these are blind ends (not circular)
to where the lymph capillaries feed
to the lymph collecting vessels
to where the lymph collecting vessels feed
to the lymph trunks
to where the lymph trunks feed
the lymph trunks drain large areas of the body and feed to the thoracic duct and the right lymphatic duct
lymph nodes
collections of WBCs along the lymph collecting vessels and lymph ducts that clean the plasma
areas drained by the right lymphatic duct
head, neck, right trunk and the right upper extremities
pathway of the right lymphatic duct
drains to the right subclavian vein
areas drained by the thoracic duct
the majority of the lymph system, excluding the head, neck, right trunk, and right upper extremities
size and weight of the heart
fist sized; about 250-300g
location of the heart
mediastinum 2/3 lies left of the mid-sternal line
orientation of the top of the heart
the base of the heart points to the right shoulder
orientation of the bottom of the heart
the apex points toward the left hip
the covering of the heart
double layered pericardium
outer layer of the pericardium
loose fibrous pericardium
make-up of the fibrous pericardium
dense CT
function of the fibrous pericardium
protects and anchors the heart
inner layer of the pericardium
serous pericardium
make-up of the serous pericardium
thin, slippery two layered serous membrane
two layers of the serous membrane
parietal pericardium and visceral pericardium or epicardium
location of the parietal pericardium
lines the inside of the fibrous pericardium
location of the epicardium
covers the surface of the heart
area between the parietal pericardium and epicardium
pericardial cavity
structure of the pericardial cavity
filled with serous fluid
function of the serous fluid in the pericardial cavity
to provide lubrication for the serous membranes to allow smooth movement during contraction and relaxation of the heart
three layers of the heart wall outer to inner
epicardium, myocardium, endocardium
structure of the epicardium
serous membrane lining the outer wall of the heart
structure of the myocardium
composed mainly of cardiac muscle and forms the bulk of the heart
endocardium
epithelial inner layer of the heart wall lining the chambers and valves of the heart
function of the endocardium
blood comes into contact with endocardium and enters the tissue
functions of the right atrium
receives the blood venous blood returning from the body through three veins
characteristic of venous blood
low oxygen content
three veins entering the right atrium
superior vena cava, inferior vena cava, coronary sinus
function of the superior vena cava
returns blood from the head, neck and upper extremities
function of the inferior vena cava
returns blood from the trunk and lower extremities
function of the coronary sinus
all veins from the heart drain into the coronary sinus which drains the coronary blood back to the right atrium
two networks in the heart
upper and lower
upper network of the heart
R & L atria
lower network of the heart
R & L Ventricles
how the upper and lower network interact
when one is performing a function, the other is doing the opposite
where the blood goes from the R atrium
passes to the right ventricle passing the tricuspid valve
function of the tricuspid valve
prevents back flow of blood from the right ventricle to the right atrium; closes when the ventricles contract and opens when they relax
functions of the right ventricle
pumps blood to the pulmonary trunk via the pulmonary valve
function of the pulmonary valve
to prevent back flow of blood from the pulmonary trunk to the right ventricle; opens when the right ventricle contracts and closes when blood fills the cusps in the valve, forcing it closed
name for blood circulation from the heart to lungs and back
pulmonary circulation
structure of the pulmonary trunk
bifurcates into the left and right pulmonary arteries
characteristics of the pulmonary arteries
only arterial flow in the body with low-oxygenated blood; bilateral set (2)
functions of the left atrium
receives oxygenated blood from the lungs via the pulmonary veins
characteristics of the pulmonary veins
only venous flow in the body with highly oxygenated blood; bilateral paired veins (4)
where the blood goes from the left atrium
passes to the left ventricle through the bicuspid or mitral valve
function of the mitral valve
prevents back flow from the left ventricle to the left atrium; closes when the ventricle contracts and opens when the ventricle relaxes
function of the left ventricle
pumps blood to the aorta via the aortic valve
function of the aortic valve
prevents back flow from the aorta to the left ventricle; closes when blood fills the cusps in the valve, forcing it closed
name of the blood circuit from the heart to the lungs and back
pulmonary circuit
name of the blood circuit from the heart to the body and back
systemic circuit
physical characteristic of the left ventricle
more muscle because it pumps blood into the high pressure systemic circuit
physical characteristic of the right ventricle
less muscle as it pumps blood into the low pressure pulmonary circuit
name for the aortic and pulmonary valves
semilunar valves
name for the tricuspid and bicuspid valves
atrioventricular valves
name of the tendons anchoring the AV valves in place
chordae tenidinae
function of the chordae tendonae
prevent the AV valves from opening the wrong way
how blood is pumped through the heart
the right side pumps blood into the pulmonary circuit and the left side simultaneously pumps blood into the systemic circuit
what provides blood supply to the heart
the coronary circulation
why separate blood supply necessary for the heart
because no nutrients pass from the blood as it passes through the chambers of the heart
from where the right and left coronary arteries arise
ascending aorta
path of the left coronary artery
bifurcates into the circumflex artery and the anterior inter-ventricular artery
to what part of the heart the circumflex artery supplies blood
the left atrium
to what part of the heart the anterior inter-ventricular artery supplies blood
the anterior ventricles
the path of the circumflex and anterior inter-vertricular arteries
from the left coronary artery then to the apex of the heart where it merges with the right coronary artery and supplies the right atrium and ventricle
path of the right coronary artery
branches at the right marginal artery and continues and branches at the posterior inter-ventricular artery then passes to the apex of the heart where it merges with the circumflex and anterior inter-ventricular arteries and supplies the right atrium and ventricle
to what part of the heart the right marginal artery supplies blood
to the anterior right ventricle
to what part of the heart the posterior inter-ventricular artery supplies blood
the posterior ventricles
to where blood from the heart drains
cardiac viens
where the cardiac veins drain
to the coronary sinus
coronary artery in which blockage is likely to lead to heart attack
left coronary artery or left inter-ventricular artery
what is the cause of myocardial infarction
blockage in the coronary arteries - particularly the left or left inter-ventricular
a sign that the AV valves in the heart are not closing all the way or may be damaged
murmur
structure of cardiac muscle
striated, skeletal muscle
mechanics of contraction of cardiac muscle
sliding filament method
characteristics of cardiac muscle cells
short, fat, branched and interconnected by intercalated discs
how some cardiac muscle cells are stimulated
self-stimulated
how the heart contracts
all or none - it does not contract by individual motor units
significance of the cardiac muscles' refractory period
longer than skeletal muscle (250 ms vs 1-2 ms) to prevent tectonic contractions
importance of O2 supply to the heart
the heart relies on aerobic respiration
nutrient supply in the heart
the heart is capable of switching metabolic pathways to use whatever nutrient supply is available
relative importance of nutrient vs O2 supply in the heart
O2 more critical due to the heart's need to function aerobically and its metabolic flexibility
autorhythmicity
the myocardium is the contractile muscle, however a portion is specialized to create electronic impulses to stimulate contraction
percentage of specialized myocardium that initiates and transmits electrical impulses throughout the heart
1%
where the electrical impulse initiate in the heart
the sino-atrial (SA) node
where the electrical impulse goes from the SA node
concurrently to the atria and the atrio-ventricular node (AV node)
where the SA and AV node are located
the right atrium
which are the most important chambers of the heart
the ventricles as they are responsible for the pumping of blood
how the ventricles are stimulated to contract and pump blood
electrical impulses from the SA and AV nodes
where the impulse from the AV node travels
the Bundle of His
location of the Bundle of His
in the inter-ventricular septum which divides the ventricles
where the impulse from the Bundle of His travels
branches into the Right and Left Bundle Branches
where the impulse travels from the Right and Left Bundle Branches
to the Purkinje Fibers
pathway of the Purkinje fibers
down the inter-ventricular septum to the apex of the heart, then upward to the walls of the ventricles; these go right into the papillary muscles
structure of the intrinsic conduction system
specialized cardiac muscle cells that initiate and distribute impulses ensuring orderly electrical impulses in the heart
complete chain of impulses in the heart
SA node, AV node, Bundle of His, Right and Left Bundle Branches, Purkinje Fibers
electrical characteristic of the SA node
unstable resting potential which generates the electrical impulse of the heart
name of the unstable resting potential in the SA node
pacemaker potential
interaction of the autonomic nervous system with the heartbeat
the sympathetic system speeds up and deepens contractions, and the parasympathetic slows them down
function of an electrocardiograph
monitors and records the electrical signals of the heart and records them
how the electrical signals of the heart are recorded
as an electrocardiogram (ECG or EKG)
contracting phase of the heart
systole
relaxing/filling phase of the heart
diastole
coordination of the atria and ventricles in contraction
the upper and lower networks act in unison - atria contract together and the ventricles contract together
term for the atria contraction
atrial systole
term for ventricular relaxation/filling
ventricular diastole
term for the ventricles contracting
ventricular systole
term for the atria relaxing/filling
atrial diastole
S1
the first heart sound "lub" - it is the sound of the AV valves closing at ventricular systole
S2
the second heart sound "dub"- the sound of the semilunar valves closing after the pressure has built in the aorta and pulmonary trunk and the cusps fill, closing the semilunar valves during ventricular diastole
how blood moves from the atria to the ventricles
after contraction, 75% of the blood falls into the ventricles after which the atria contract slightly to pump the rest into the ventricles - atrial systole
what causes a murmur
the turbulent back flow of blood through a valve that does not close tightly
term for the contractile phase of the cardiac cycle
systole
term for the relaxation phase of the cardiac cycle
diastole
definition of the cardiac cycle
the series of pressure and volume changes in the heart during one heartbeat
ventricular filling
during mid to late ventricular diastole - AV valves open, SL valves closed and blood flow passively from atria to ventricles; end of ventricular diastole the atria contract (atrial systole) and push the last of the blood into the ventricles
phase in the cardiac cycle during which blood is pumped into the pulmonary trunk and aorta
ventricular systole - the atria relax (atrial diastole) and the ventricles contract (ventricular systole), closing the AV vlaves and opening the SL valves
what causes the SL valves to close and the AV valves to open
isovolumetric relaxation - during early ventricular diastole the ventricular pressure drops
cardiac output
the amount of blood pumped out of the ventricle per minute
how cardiac output is calculated
the product of stroke volume and heart rate
equation for cardiac output
CO = SV x HR
Classification of blood
Blood is a specialized form of CT
what makes blood a type of CT
composed of living cells, or formal elements, suspended in a non-living matrix (fluid)
The fluid matrix of blood
plasma
Three components of blood
RBC, WBC, platelets
the three layers of centrifuged blood (top to bottom)
Plasma, buffy coat, erythrocytes
characteristics of erythrocytes
RBC's - heaviest and most numerous and dense element
%age of whole blood that is erythrocytes
45%
what the %age of erythrocytes in blood is called
hematocrit - normal range 36%-50%
characteristics of the buffy coat
leukocytes (WBC's) and platelets - smallest element
%age of whole blood that is Leukocytes
<1%
critical function of platelets
clotting
the pH range of blood
slightly basic - 7.35-7.45
density and viscosity of blood
slightly higher than water
why pH is so important to blood
critical enzymes don't function out of the 7.35-7.45 pH range
volume of blood
5-6 liters in males and 4-5 liters for women
functions of blood
distribution, body regulation, and protection
distribution function of blood
oxygen, nutrients, elimination of wastes, distribution of endocrine hormones
method of oxygen distribution by the blood
from the lungs via RBC
method of nutrient distribution
from the GI tract via plasma
method of elimination of wastes distribution
via plasma to the lungs for gas and to the kidneys for nitrogenous wastes
method of endocrine hormone distribution
via the plasma to various parts of the body
regulation function of blood
body temperature, pH balance, and fluid volume
method of body temperature regulation
absorption and distributing heat to the body and skin surface
method of pH balance
blood proteins and solutes help maintain pH of system
method of fluid volume regulation
water homeostasis vis salts and blood proteins in the plasma
protection function of blood
protects against excessive blood loss via clotting and the immune system
clotting element of blood protective function
platelets are one key element
immune system
leukocytes protect the body from infection
characteristics of blood plasma
sticky, straw colored fluid 90% water, the rest is solutes - nutrients, gases, hormones, wastes, products of cell activity, ions, and proteins
plasma protein content
8% of plasma
largest protein component of blood
60% albumin
functions of albumin
many hormones are carried by albumin and it is responsible for osmotic pressure in blood
where albumin is produced
liver
what poor osmotic pressure in blood causes
leaking fluids leading to edema
characteristics of erythrocytes (RBC's)
small, biconcave, lack nuclei and most organelles - mostly contain hemoglobin
function of hemoglobin
oxygen binding pigment responsible for transporting most of the O2 in blood
structure of hemoglobin
globin protein bound to the heme pigment
structure of heme
iron centric surrounded by N
number of hemes in each RBC
4
globin structure
4 polypeptides attached to heme via shared N
types of poly peptides in globin
2 - alpha and beta
number of globins in each RBC
4 total in 2 sets - 2 alphas and 2 betas
where O2 binds in hemoglobin
to the hemes - up to 4 O2
percentage of saturation in blood
1 through 4 O2 molecules per RBC = 25% to 100%
lifespan of a healthy RBC
120 days
where dead RBC's are "recycled"
spleen
where excess iron is stored if not needed to form hemes
liver
how iron is stored in the liver
bound to ferritin
what is produced in the spleen when iron is removed from the RBC
non-iron heme
how non-iron heme is processed
in the spleen it is converted to biliverdin then to bilirubin and transported to the liver where it is converted into bile and stored
condition caused by excess bilirubin in the system
jaundice
term for blood cell formation
hematopoeisis
where hematopoeisis occurs
in the bone marrow
term for the formation of RBC's
erythropoeisis
process of erythropoeisis
hemocytoblast becomes a myeloid stem cell becomes a proerythroblast which then develops into a mature RBC
last stage of erythropoeisis in the marrow
reticulocyte - when the nucleus is ejected from the developing RBC
what happens when the reticulocyte is formed
it leaves the marrow and becomes a an erythrocyte in 12-24 hours after leaving the marrow
normal range of reticulocyte count in the blood
.5-1%
what a high reticulocyte count may indicate
excessive hemolysis
what controls erythrocyte production
erythropoietin
how blood O2 level homeostasis is achieved
when O2 levels in the blood drop, blood cells are produced
erythropoietic mechanism
O2 levels drop due to decreased RBC, hemoglobin or O2 supply; Kidney (and liver) produce erythropoietin; erythropoietin stimulates hemocytoblast differentiation in the marrow; RBC count increases; O2 in the blood increases with more healthy RBC's
dietary requirements for RBC production
iron, B12, folic acid, proteins, lipids, and carbohydrates
how iron is processed in erythropoiesis
stored in liver as ferritin and hemosiderin; transported loosely bound to transferrin
how B12 and folic acid is used in erythropoiesis
necessary for the DNA synthesis in cell division
erythrocyte disorders
anemia - RBC deficiency; polycythemia - RBC excess; sickle cell - misshaped RBC's due to an amino acid substitution in the DNA
distinctive fact of leukocytes
only formed element in blood that are complete cells and makeup <1% of blood volume
role of leukocytes
immune system - critical for fighting disease
categories of leukocytes
phagocytes and lymphocytes
characteristic of granulocytes
large cells, lobed nuclei, phagocytic, stain with granule appearance
three type of granulocytes
neutrophils, eosinophils, basophils
function of neutrophils
most numerous leukocyte, attracted to inflammation sites and are actively phagocytic
function of eosinophils
uncommon and attack parasites
function of basophils
least numerous leukocyte and release histamines in the inflammatory response
characteristics of agranulocytes
lymphocytes that lack visibly staining granules
types of lymphocytes
monocytes, B-lymphocytes, and T-lymphocytes
function of T-cells
directly attack virus infected and tumor cells
function of B-cells
become plasma cell when in contact with pathogen; plasma cells secrete antibodies -immunoglobulins
function of monocytes
become macrophages and activate T-Cells
T-cell production
immature cells are sent from bone marrow to the thymus gland and are exposed to foreign and self antigens; those that respond to self-antigens are destroyed others are released into the blood
term for the formation of WBC's
leukopoiesis
how leukopoiesis is regulated
by the production of interleukins and colony-stimulating factors
process of leukopoiesis
hemocytoblasts are differentiated along two pathways: lymphoid and myeloid stem cells
cells produced on the lymphoid stem cell path
lymphocytes (T-cells and B-Cells)
cells produced on the myeloid stem cell path
granulocytes and monocytes
pathology of Leukocytes
high count= leukocytosis; low count=leukopenia; =
production of unspecialized WBC that divide cancerously
leukemia
cause of infectious mononucleosis
Epstein-Barr virus
term for the buildup of cancerous cells
SOL - space occupying lesion
characteristic of platelets
not complete cells
formation of platelets
fragment of megakaryocytes formed by the repeated mitosis without cytokinesis
function of platelets
critical to clotting by forming a temporary seal when a vessel is broken
treatment for substantial blood loss or thrombocytopenia
whole blood transfusion
treatment for low blood volume
plasma and blood volume expander are given
term for antigens on the cell walls of RBC's
agglutinogens
term for preformed antibodies in the plasma
agglutinins
characteristics of AB blood type
has both A and B agglutinogens, but no agglutinins
Characteristics of A blood type
has A agglutinogens, and B agglutinins
characteristics of B blood type
has B agglutinogens and A agglutinins
characteristics of O blood type
no agglutinogens and A and B agglutinins
how a transfusion reaction occurs
the donors blood is attacked by the recipient's agglutinins (antibodies)
what happens in a transfusion reaction
the agglutinins cause agglutination (clumping of the foreign cells) and hemolysis of the foreign cells occurs
Rh factor
the presence (+) or absence (-) of a group of RBC antigens
where RH factor received its name
Rhesus monkeys
two main groups of the organs of the digestive system
alimentary canal and accessory organs
another term for the alimentary canal
gastro intestinal tract (GI tract)
the alimentary canal
the continuous muscular digestive tube that winds through the body
organs of the alimentary canal
mouth, pharynx, esophagus, stomach, small intestine, large intestine
function of accessory organs
aid digestion physically and produce secretion to breakdown foodstuff in the GI tract
the accessory organs
teeth, tongue, gallbladder, salivary glands, liver, pancreas
definition of the digestive process
the ingestion, breakdown and absorption of macronutrients
macronutrients
fat, protein, carbohydrates
elements of the digestive process
ingestion, propulsion, mechanical digestion, chemical digestion, absorption, defecation
definition of ingestion
the act of putting food in your mouth
definition of propulsion
the motility/movement of food through the GI tract
two elements of propulsion
swallowing, peristalsis
definition of mechanical digestion
the physical process of preparing the food for chemical digestion
the four elements of mechanical digestion
chewing, mixing, churning, and segmentation
definition of chemical digestion
a series of catabolic steps in which complex food molecules are broken down to their chemical building blocks by enzymes
definition of absorption
the passage of digested end products from the lumen of the GI tract through the mucosal cells into the blood or lymph
where the macronutrients are absorbed
proteins and carbs to the blood and fats to the lymph
definition of defecation
the elimination of indigestible substances from the body via the anus as feces
the sole purpose of the digestive system
to optimize digestion
how the sole purpose of digestion differs from other organ systems
other organ systems are designed to maintain levels of substances in the blood
how digestive activity is triggered
mechanical and chemical stimuli
process of mechanical stimulation of the GI tract
sensors detect distention
process of chemical stimulation of the GI tract
sensors detect chemicals in the GI tract - i.e. the presence of fat, proteins, and glucose
two types of controls of the Digestive system
intrinsic and extrinsic
intrinsic controls of the DS
hormones - some enhance and some impair the DS
extrinsic controls of the DS
nervous system control - parasympathetic system, i.e. rest & digest
what covers the external surface of most of the digestive organs
visceral peritoneum
what lines the wall of the abdomino-pelvic cavity
parietal peritoneum
what lies between the visceral and parietal peritoneums
peritoneal cavity
what fills the peritoneal cavity
serous fluid
composition of the mesentery
double layer of peritoneum that extends from the body wall to surround the digestive organs
functions of the mesentery
allows blood vessels, lymphatics, and nerves to reach the digestive organs; holds the organs in place; stores fat
how the mesentery is formed
a double layered fold of the parietal peritoneum extends from the posterior body wall, forming the mesentery until it becomes the visceral peritoneum as it surrounds the digestive organs
the five different mesenteries
mesentery proper, mesocolon, greater omentum, lesser omentum, falciform ligament
mesentery proper
runs from the posterior abdominal wall to the SI and covers the SI
mesocolon
runs from the posterior abdominal wall to the LI and covers the LI
greater omentum
an apron of mesentery arising from the visceral peritoneum of the stomach at the greater curvature and running to cover the small intestine, the spleen and transverse LI where it attaches to the mesocolon
lesser omentum
mesentery arising from the visceral peritoneum of the liver and running to the lesser curvature of the stomach
falciform ligament
mesentery arising from the anterior abdominal wall attaching to the liver, separating the right and left lobes anteriorly and suspending the liver from the diaphragm
retroperitoneal organs
organs that lie posterior to the mesentery on the dorsal abdominal wall
how organs became retroperitoneal
moved outside of the mesentery during embryonic development
the retroperitoneal organs
duodenum, pancreas, ascending colon, descending colon, rectum
splanchnic circulation
the arterial supply of the DS branching from the abdominal aorta and the hepatic portal circulation
hepatic portal circulation
the venous portion of the splanchnic circulation carrying nutrient rich blood from the digestive organs to the liver
four layers of the tissue of the alimentary canal
mucosa, submucosa, muscularis externa, serosa
mucosa
innermost, moist epithelial membrane lining the entire GI tract
functions of the mucosa (3)
secretes mucus, digestive enzymes and hormones; absorbs digestive end products into the blood; protects against infectious disease
3 layers of the mucosa
epithelium, lamina propria, muscularis mucosa
composition and function of the mucosal epithelium
simple columnar epithelial tissue that secretes mucous protecting the organs from the digestive process
composition and function of the lamina propria
loose areolar CT that houses pockets of MALT - mucosa associated lymphatic tissue - that help defend against infectious disease
Peyer's patches
areas of MALT in the mucosa that extend to the submucosa
composition and function of the muscularis mucosa
smooth muscle that produces local movement in the mucosa and, in a constant state of tone, creates the folds of the mucosa to increase surface area for absorption
composition the submucosa
areolar CT with elasticity that allow the GI tact to expand and contract; contains lymph vessels and lymphoid follicle and is highly vascularized, providing blood supply for surrounding tissue layers
meissner's plexus
network of nerve fibers in the submucosa - aka submucosal nerve plexus - that helps control secretions
two levels of the muscularis externa
inner, circular layer of muscle and an outer, longitudinal layer of muscle
function of the muscularis externa
movement by contraction; thickens to sphincters incrementally along the GIT to prevent backflow
myenteric plexus
nerve network in the muscularis externa that is responsible for movement
composition of the serosa
the visceral peritoneum surrounding the AC - areolar CT lined with the mesothelium - simple squamous epithelial cells
nervous supply of the alimentary canal
supplied by enteric neurons that connect to the two plexuses of the AC; this intrinsic nervous supply is enhanced extrinsically by the parasympathetic nervous response
composition of the mouth
a stratified squamous epithelial mucosa lined cavity bound by the lips, cheeks, palate and tongue
composition and function of the lips and cheeks
skeletal muscle covered by skin that functions to keep food between the teeth during mastication
composition of the palate
forms the roof of the mouth in two parts - hard palate anteriorly and soft palate posteriorly
composition and function of the tongue
interlacing intrinsic and extrinsic skeletal muscle to reposition food when chewing, mix food with saliva, initiate swallowing and to form consonants for speech
intrinsic muscle of the tongue
originates and inserts on the tongue
extrinsic muscle of the tongue
originates elsewhere and inserts on the tongue - generally for in/out and side to side movements
salivary glands' function
produce saliva which: cleans the mouth; dissolves food chemicals for taste; moistens food; contains chemicals begin the breakdown of starches
name of the enzyme responsible for initiating the breakdown of starch
salivary amylase
composition and function of the pharynx
the oropharynx and laryngopharynx provide a common passageway for food, fluids and air
composition and function of the esophagus
runs from the laryngopharynx to the cardiac orifice of the stomach providing a passage for food and fluids
two stages of the digestive process in the mouth and esophagus
mastication and deglutition
mastication
chewing - begins the mechanical breakdown of food
deglutition
swallowing - occurs in two phases: buccal and pharyngeal-esophageal phase
buccal phase of swallowing
voluntary and occurs in the mouth as bolus is forced into the oropharynx
pharyngeal-esophageal phase of swallowing
involuntary and occurs as bolus is squeezed through the pharynx into the esophagus
function of the stomach
temporary storage tank for food where the chemical breakdown of proteins in initiated and food is converted to chyme
chyme
food broken down to a mushy liquid for processing
size of the adult stomach
15-25 cm long with diameter and volume dependent on its contents
major regions of the stomach
cardiac, fundus, body, pyloric
cardiac region
the entrance to the stomach; connected to the esophagus by the cardiac orifice
fundus
area at the top of the stomach above the cardiac orifice
body
most of the stomach - from the fundus to the pyloric region
pyloric region
starts roughly at the bottom of the greater and lesser curvature; three regions
three areas of the pyloric region
pyloric antrum, pyloric canal, pylorus
pyloric antrum
the broad area of the pyloric region at the base of the curvatures
pyloric canal
where the pyloric region narrows as it leads to the pylorus
pylorus
the distal end of the stomach that connects to the duodenum; terminates at the pyloric valve or sphincter which controls gastric emptying
lateral outer convex surface of the stomach
greater curvature
medial outer convex surface of the stomach
lesser curvature
composition of the stomach mucosa
simple columnar epithelium
gastric glands function
produce gastric juices containing mucous, HCl, intrinsic factor, pepsinogen and hormones
structure of gastric glands
formed in the epithelial layer of the mucosa - gastric pits descend to the gastric gland below consisting of goblet cells (mucous neck cells), parietal cells, chief cells and entero-endocrine cells
goblet cells function
produce mucous to protect the stomach from gastric juices and the digestive process
parietal cells function
produce HCl (to breakdown proteins) and intrinsic factor (to absorb B-12)
chief cells function
produce pepsinogen - a proteolytic enzyme that is inactive until combined with HCl and becomes pepsin
entero-endocrine cells function
produces hormones
gross anatomy of the small intestine
extends from the pyloric sphincter to the ileocecal valve, connecting to the LI
three subdivisions of the Small Intestine
duodenum, jejunum, and the ileum
section of the small intestine where most of the absorption of the GI tract occurs
jejunum
the deep circular folds of the mucosa and submucosa of the SI
plicae circulares
function of the plicae circulares
to increase the surface area of the mucosa of the SI for more absorption
villi
small, fingerlike projections of the mucosa of the SI for increased absorptive ability
microvilli
small fingerlike projections of the absorptive cells on the villi of the mucosa
the brush border
the brush like appearance of the absorptive cells of the villi of the SI created by the conglomeration of the microvilli
brush border enzymes
enzymes in the brush border that complete the digestion of carbs and proteins on the SI
components of the villi
the villi of the epithelial layer of the SI mucosa contains absorptive cells and goblet cells; the lamina propria contains lacteal and dense capillary supply
components of the mucosa of the SI not in the villi
the lamina propria below the villi contains MALT and intestinal crypts or crypts of Lieberkühn which contain enteroendocrine cells and absorptive cells
lacteal
a thick lymph passage in the center of the villi
function of the crypts of Lieberkühn
secretes intestinal juice that acts as a carrier fluid for the absorption of nutrients from the chyme and hormones
gross anatomy of the liver
it is the largest gland in the body and has four lobes; the largest is the right lobe
what separates the right and left lobes of the liver
the falciform ligament (mesentery)
functional unit of the liver
lobules - made of plates of liver cells (hepatocytes)
digestive function of the liver
produces bile
bile
a yellow-green, alkaline solution that emulsifies fat (reduces its surface tension)
duct through which bile is sent to the duodenum
common hepatic duct which meets the cystic duct and forms the bile duct
where bile that is not needed is stored and concentrated
the gall bladder; concentrates the bile as water leaves the GB
duct that connects the gall bladder to the liver and duodenum
the cystic duct connects the GB to the liver via the common hepatic duct and the duodenum via the bile duct
how bile typically enters the small intestine
when the gall bladder contracts
substance that causes the gall bladder to contract
cholecystokinin
function of the pancreas in digestion
an accessory gland that is retroperitoneal and secretes pancreatic juice to the duodenum to assist with the digestion of proteins, carbs and fats
composition of pancreatic juice
mostly water containing enzymes that breakdown food and electrolytes
how the secretion of pancreatic juice is regulated
local hormones and the parasympathetic nervous systems
functions of the large intestine
reabsorption of water and the elimination of indigestible materials as feces
three unique features of the LI
teniae coli, haustra, epiglopic appendages
teniae coli
the singular longitudinal layer or the muscularis externa in the LI that is in a continuous state of tone, creating pockets in the LI called haustra
haustra
the pockets in the LI created by the teniae coli
epiglopic appendages
fat-filled pouches in the visceral peritoneum whose function is unknown
five subdivisions of the LI
cecum, appendix, colon, rectum and anal canal
cecum
the "blind pouch" which lies below the ileocecal valve connecting the LI to the SI and is the first part of the LI
vermiform appendix
contains MALT and is important in the immune system
colon
the retroperitoneal portion of the LI except the transverse and sigmoid portions
major subdivisions of the colon
ascending colon, hepatic flexure, transverse colon, splenic flexure, descending colon, sigmoid colon
part of the LI distal to the sigmoid colon
the rectum
the part of the LI distal to the rectum and the last segment of the LI
the anal canal which contains the internal and external anal sphincters
the distal, exterior opening of the GI tract
the anus
source of bacteria in the colon and their function
enter the colon via the SI and anus and aid in the fermentation of indigestible carbs