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Lab 4

Terms in this set (37)

•Closed transport system
Heart → large arteries → medium arteries → arterioles → capillary beds → venules → medium veins → large veins → heart
Substances diffuse across what
capillary walls
O2 and nutrients from blood to tissues
Waste and CO2 from tissues to blood
Tunica intima
•Innermost layer
•Thin layer of endothelium with CT basement membrane
Tunica media
•Circularly arranged smooth muscle and elastic CT
•Allows for changes in lumen diameter
tunica externa
•Most superficial•
Protects and anchors vessels
•Areolar or fibrous CT
What are arteries?
transport blood away from the heart
-Expands during systole, recoils passively during diastole
-Elastic arteries: close to the heart, large, "conducting vessels", most expandable
-Muscular arteries: medium-sized, "distributing vessels", named arteries in the body
-Arterioles: smallest, "resistance vessels"
Capillaries
provide for exchange of materials in tissues
•narrowest vessels, walls = endothelium (one cell layer)
Venis
transport blood toward the heart
•65% of blood volume is in the veins
•Low pressure vessels because of thin walls and large lumens
•Adaptations for venous return blood to Right Atrium:
Venis( part 2)
•Valves: formed by folds of tunica intima
•Prevent backflow
•Highly concentrated in the limbs
•Skeletal muscle pump
•Respiratory pump
Mechanisms of venous return
•The heart pumps blood through the arteries, but pressure is low by the time blood reaches the veins
•Valves in veins prevent backflow of blood
•Skeletal muscle pump: skeletal muscle contractions squeeze veins
Respiratory pump
during inspiration, a decrease in intra-thoracic pressure and increase in intra-abdominal pressure causes blood to flow from veins in the abdominal region to veins in the thoracic region
The aorta
•Largest artery in the body
•Leaves from the left ventricle of the heart
regions of the aorta
ascending aorta (leaves the left ventricle)
, aortic arch (arches to the left)
thoracic aorta (travels downward through the thorax),
abdominal aorta(passes through the diaphragm into the abdominopelvic cavity)
Arterial branches of the ascending aorta and aortic arch
•Ascending aorta (Right and left coronary arteries serve the heart)
Aortic arch (•Brachiocephalic trunk) Then splits into the: right common carotid artery and right subclavian artery
Left common carotid artery (Then splits into the left internal and external carotid arteries)
Left subclavian artery •Then branches into the left vertebral artery and left subclavian artery•Subclavian artery becomes axillary artery → brachial artery → radial and ulnar arteries
Arterial branches of the descending thoracic aorta
•Intercostal arteries
- Supply the muscles of the thorax wall
•Bronchial arteries(Supply the lungs)
•Esophageal arteries (Serve the esophagus)
•Phrenic arteries (Serve the diaphragm)
Special circulations: Coronary circulation
•Blood in the heart chambers does not nourish the myocardium
•The heart has its own nourishing circulatory system consisting of:•Coronary arteries branch from the aorta to supply the heart muscle with oxygenated blood
•Cardiac veins drain the myocardium of blood
•Coronary sinus, a large vein on the posterior of the heart, receives blood from cardiac veins
•Blood empties into the right atrium via the coronary sinus
Special circulations:Pulmonary circulation
•Capillary beds around alveoli permit gas exchange (exchange CO2 for O2)
•Nourishing blood supply for the lungs provided by bronchial arteries, not pulmonary circulation
Special circulations:Hepatic portal system
•Veins of hepatic portal circulation drain the
•Digestive organs
•Spleen
•Pancreas
Major vessels of hepatic portal circulation
•Inferior and superior mesenteric veins
•Splenic vein
•Left gastric vein
Special circulations:Hepatic portal system
•Capillary beds of the digestive system absorb nutrients and toxins
•Hepatic portal vein carries this blood to the liver
•Liver helps maintain proper glucose, fat, and protein concentrations in blood
•Liver also filters toxins from the blood
•Blood drains into the hepatic vein as it leaves the liver
Special circulations:Cerebral arterial circle
•Also called the circle of Willis
•Internal carotid arteries divide into anterior and middle cerebral arteries (These arteries supply most of the cerebrum)
Vertebral arteries join once within the skull to form
the basilar artery
•Basilar artery serves the brain stem and cerebellum
Posterior cerebral arteries form from the
division of the basilar artery
•These arteries supple the posterior cerebrum
Anterior and posterior blood supplies are united by
small communicating arterial branches
The vena cava
•Superior and inferior vena cava enter the right atrium of the heart
•Superior vena cava drains the head and arms
•Inferior vena cava drains the lower body
Draining the arm:
•Radial and ulnar veins → brachial vein → axillary vein
•Cephalic vein drains the lateral aspect of the arm and empties into the axillary vein
•Basilic vein drains the medial aspect of the arm and empties into the brachial vein
•Basilic and cephalic veins are jointed at the median cubital vein (elbow area
Subclavian vein receives
•Venous blood from axillary vein
•Venous blood from skin and muscles of head and neck via external jugular vein
Vertebral vein drains the what and the Internal jugular vein drains the what Azygous vein drains the what
posterior part of the head and the dural sinuses of the brain, the thorax
Left and right brachiocephalic veins receive venous blood from the
•Subclavian veins
•Vertebral veins
•Internal jugular veins
Brachiocephalic veins join to form
superior vena cava
Azgous vein drains the what
throax
Anterior and posterior tibial veins and fibial veins drain what
the legs
Great saphenous veins are what are receive what
longest veins of the body) receive superficial drainage of the legs
Each common iliac vein (left and right) is formed by
Right gonadal vein drains the
Left gonadal vein empties
Left and right renal veins drain
Hepatic portal vein drains the what and travels where
Left and right hepatic veins drain
-the union of the internal and external iliac vein on its own side
-right ovary in females and right testicle in males
- into the left renal vein
- drain the kidneys
- digestive organs and travels through the liver before it enters systemic circulation
- the liver
Veins draining into the inferior vena cava
> >. > >
Posterior tibial vein → popliteal vein → femoral vein → external iliac vein
Fetus receives exchanges of what
Umbilical vein
Umbilical arteries (two of them)
-of gases, nutrients, and wastes through the placenta
-carries blood rich in nutrients and oxygen to the fetus
-carry carbon dioxide and debris-laden blood from fetus to placenta
Blood flow bypasses then Blood flow bypasses the
Blood entering the right atrium is
Ductus arteriosus connects
-liver through the ductus venosus and enters the inferior vena cava then by passes the lungs
- shunted directly into the left atrium through the foramen ovale
-the aorta and pulmonary trunk (becomes ligamentum arteriosum at birth)
Development of the circulatory system in the fetus

-A simple "tube heart" (without chambers) develops in
The heart becomes a four-chambered organ
Few structural changes occur after
-the embryo and pumps by the fourth week post-fertilization
- by the end of seven weeks post-fertilization
-the seventh week post-fertilization
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