A&P II Ch. 20-21

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Terms in this set (...)

The usual route of blood flow around the body is...
Heart to arteries to arterioles to capillaries to venules, then veins and back to the heart
An artery is...
any vessel that carries blood AWAY from the heart
A vein is...
any vessel that carries blood TOWARD the heart
Anastomoses
are places where two veins are arteries merge
Tunica Externa
(tunica adventitia) is the outermost layer, made up of loose connective tissue. It anchors the vessel
Tunica Media
(middle tunic) is the thickest layer of the vessel, made up of mostly smooth muscle. Is responsible for vasomotion
Tunica Inerna
(tunica intima) consists of endothelium overlying a basement membrane and a sparse layer of fibroconnective tissue. It provides a smooth surrounding through which blood passes.
Conducting, or elastic arteries are...
the largest and are subject to the highest blood pressure
Distributing (muscular) arteries
distribute blood to specific organs
Resistance (small) arteries
the primary means of controlling the routes of blood flow
Arterioles
the smallest of the resistance arteries
Metarterioles
link with arterioles and capillaries
Capillaries
the vessels through which materials are exchanged between blood and the tissue fluid (consist of endothelium only)
Capillaries are organized into...
capillary beds of 10-100 capillaries, with a thoroughfare channel that can bypass the bed when needed and carry blood directly to a venule
Continuous capillaries
their endothelial cells are held tightly together by tight junctions and form an uninterrupted tube
Fenestrated capillaries
have endothelial cells riddled with holes
Sinusoids
are blood filled spaces
Venules
collect blood from capillaries
Veins
have much lower blood pressure than arteries because of their distance away from the heart
Veins often have...
internal valves to prevent the back flow of blood when skeletal muscle relaxes
Blood flow
is the amount of blood flowing through an organ, tissue, or vessel in a given time (ml/min.)
Perfusion
is the rate of blood flow per given volume or mass of tissue (flow/g)
Sphygmomanometer is employed...
systolic pressure, which indicates the peak arterial pressure during ventricular systole; and diastolic pressure, which is the minimum arterial pressure between heart beats
Hypertension
a chronic resting systolic pressure of 140 mmHg or higher, or a diastolic pressure higher than 90mmHg
Hypotension
a chronic low resting blood pressure may be due to loss, dehydration, or anemia
Blood pressure
is determined mainly by cardiac output, blood volume, and peripheral
Peripheral Resistance
is the resistance that the blood encounters in the vessels as it travels away from the heart
Blood Viscosity
mostly due to erythrocytes and albumin
Vessel Length
pressure and flow decline with increasing distance
Vessel Radius
exerts a powerful influence over flow
Autoregulation
is the ability of tissue to regulate their own blood supply
Neural Control
some sympathetic fibers induce vasoconstriction while other trigger vasodilation
Hormonal Control
angiotensin II is a potent vasoconstrictor ADH is also a vasoconstrictor in high concentrations
Capillary exchange
refers to the two-way movement of substance between capillaries and tissue fluid
Diffusion
the most important mechanism of exchange
Transcytosis
endothelial cells pick up droplets of fluid on one side of the plasma membrane by pinocytosis, transport the vesicles across the cell, and discharge it on the other side by exocytosis
Venous return
the flow of blood back to the heart, is achieved by pressure gradient
Pressure gradient
blood flows from higher pressure to a lower one on its return to the heart
Thoracic pump
breathing muscles help return blood to the heart
Cardiac suction
within the ventricles due to the action of the chordae tendineae
Skeletal muscle pump
skeletal muscle squeezes against veins
Gravity
aiding in return of blood from your head
Circulatory shock
a state in which cardiac output is not sufficient to meet the body's needs
Cardiogenic shock
occurs because the heart is not beating adequately, perhaps from a MI
Low venous return shock
all other forms are due to (LVR) shock
Cerebrovascular accident
(CVA, or stroke) is death of brain tissue caused by ischemia resulting from cerebral atherosclerosis, thrombosis, or ruptured aneurysm
Transient ischemic attack
(TIA) is a temporary feeling of dizziness, loss of sensations, weakness, or aphasia, which results from brief periods of cerebral ischemia (poor blood flow)
Lymphatic system
its functions are fluid recovery, immunity, and lipid absorption
Lymph
once tissue has entered the lymphatic vessel it is called lymph, it is usually clear and colorless, and is similar in composition to blood plasma but contains less protein
Lymphatic vessels
have the same three tunics as blood vessels, but their walls are thinner and their valves are more numerous
Lymph flows...
under the same forces that guide the venous return to the heart, also through several nodes in series before returning to the bloodstream
Lymph is moved...
primarily by rhythmic contractions of the lymphatic vessels themselves, but also aided by skeletal and respiratory pumps
Lymph nodes
are numerous and embedded within connective tissue, bean-shaped structure, less than 3cm in length with hilum on one side, filter lymph
Macrophages
are concentrated in the medulla of the lymph node
Lymphocytes
are located in the parenchymal cortex, where germinal centers arise when fighting off a pathogen
Tonsils
each is covered by epithelium lined with deep pits that entrap ingested and inhaled pathogens, and introduced them to lymphocytes
Palatine
Are the largest and most often infected; removed during tonsillectomy ,lingual, and adenoids tonsil
Thymus
Is the largest and most active during childhood, but undergoes involution after the age of 14, each lobule has a medulla occupied by lymphocytes, is both lymphatic and endocrine in function
Within the spleen
Red pulp consists of sinuses filled with erythrocytes, and white pulp consists of lymphocytes and macrophages
Spleen
Produces blood cells in the fetus, serves as a blood reservoir, acts as an erythrocytes graveyard, and filters the blood
Nonspecific resistance
Defenses that guard against a wide variety of pathogens; and immunity, composed of mechanisms whereby lymphocytes recognize and destroy specific pathogens
The skin's surface
Is composed mostly of impervious Kerstin that few pathogens can penetrate
Mucous membrane
Mucus traps microbes and contains protective chemicals
Connective tissue gel
hyaluronic acid inhibits the dread of pathogens through connective tissues
Chemical barriers
Stomach acid, lactic acid in perspiration, acid in the urethra and lysozyme in tears, saliva, and mucus all serve to deter pathogens
Neutrophils
Are highly mobile, and spend their time wandering the connective tissue phagocytizing bacteria
Eosinophils
phagocytize antigen-antibody complexes, allergens, and inflammatory chemicals
Basophils
Secrete the vasodilator histamine and the anticoagulant heparin
Natural killer cells
(NK) are large lymphocytes that attack cells of your own body that are infected by viruses or have turned cancerous
Monocytes
Are the circulating precursors of macrophages
Inflammation
Is a response to tissue injury, and is characterized by redness, swelling, heat, pain, and impaired function
Interferons
Are polypeptides secreted by cells that have been invaded by viruses, they diffuse to neighboring cells and prevent viruses from attaching to them
Complement system
A group of 20 or more beta globulins of blood that aid nonspecific resistance and immunity
Fever
Promotes interferon activity, elevates metabolic rate and accelerates tissue repair, and it inhibits the reproduction of bacteria and viruses
Antigens
(Ag) any molecule that triggers an immune response, large complex molecules such as proteins, uniqueness allows the immune system to distinguish self from non-self
Haptens
Can stimulate an immune response by binding to a host macromolecule
Antibody
(Ab) or immunoglobulin, is a gamma globulin, basic structure is composed of four polypeptide chain linked by disulfide bonds, each chain has a variable region that makes each antibody unique, the rest of each chain is a constant region
Humoral immunity
essential stages are recognition, attack, and memory