Biology Forums - Study Force

1.   Cross-sectional views of an artery and of a vein.
Artery: round and thick
Vein: thin and squiggly

Characteristics of tunica intima
Innermost tunic, thin tunic of capillaries, has a smooth surface to decrease resistance to blood flow.

Characteristics of tunica media
Especially thick in elastic arteries, contains smooth muscle and elastin

Characteristics of tunica externa
Most superficial tunic

2.   Why are valves present in veins but not in arteries?
Veins need valves to create pressure to pump the blood back to the heart; working against gravity. Arteries do not need them because blood is supposed to flow away from the heart; working along with gravity.

3.   Name two events occurring within the body that aid in venous return.
Skeletal muscle “milking action” and changes in thoracic cavity pressure during breathing.

4.   Why are the walls of arteries proportionately thicker than those of the corresponding veins?
Arteries directly take blood from the heart. They need to withstand the direct pressure of the contractions.

MAJOR SYSTEMIC ARTERIES AND VEINS OF THE BODY
5.   MATCHING
1.   The arterial system has one of these; the venous system has two. Brachiocephalic

2.   These arteries supply the myocardium      Coronary

3.   Two paired arteries serving the brain      Internal carotid, Vertebral

4.   Longest vein in the lower limb   Great Saphenous

5.   Artery on the dorsum of the foot checked after leg surgery   Dorsalis pedis

6.   Serves the posterior thigh   Deep artery of the thigh

7.   Supplies the diaphragm   Phrenic

8.   Formed by the union of the radial and ulnar veins   Brachial

9.   Two superficial veins of the arm   Basilic, cephalic

10.   Artery serving the kidney      Renal

11.   Veins draining the liver      Hepatic

12.   Artery that supplies the distal half of the large intestine      Inferior mesenteric

13.   Drains the pelvic organs      Internal iliac

14.   What the external iliac artery becomes on entry into the thigh    Femoral

15.   Major artery serving the arm      Subclavian

16.   Supplies most of the small intestine   Superior mesenteric

17.   Join to form the inferior vena cava      Common iliac

18.   An arterial trunk that has three major branches, which run to the liver, spleen, and stomach.               Celiac Trunk

19.   Major artery serving the tissues external to the skull      Common Carotid

20.   Three veins serving the leg      Anterior tibial, Fibular, Posterior tibial

21.   Artery generally used to take the pulse at the wrist      Radial

6.   What is the function of the cerebral arterial circle (circle of willis)?
It provides an alternate pathway for blood to reach brain tissue in the case of impaired blood flow somewhere in the system.

7.   The anterior and middle cerebral arteries arise from the Internal carotid artery. They serve the cerebrum of the brain.

8.   Trace the pathway of a drop of blood from the aorta to the left occipital lobe of the brain, noting all structures through which it flows?
Aortic arch-->Left Subclavian Artery-->Left Vertebral Artery-->Transverse Foramina-->Posterior Arch of Atlas Vertebrae-->Foramen Magnum-->Right Vertebral Artery-->Basilar Artery-->Posterior Cerebral Artery-->Parietooccipital Artery-->Occipital Lobe

9.   SEE ATTACHED PHOTO

10.   BLOOD FLOW SITUATIONS
A.   From the capillary beds of the left thumb to the capillary beds of the right thumb:    
Digital Vein-->Left Radial Vein-->Left Brachial Vein-->Left Axillary Vein-->Left Subclavian Vein-->Left Brachiocephalic Vein-->Superior Vena Cava-->Right Atrium-->Right Ventricle-->Pulmonary Trunk-->Pulmonary Artery-->Lobar Artery-->Pulmonary Capillaries Of The Lung-->Lobar Veins-->Pulmonary Veins-->Left Atrium-->Left Ventricle-->Aortic Arch-->Brachiocephalic Artery-->Right Subclavian Artery-->Right Axillary Artery-->Right Brachial Artery-->Right Radial Artery-->Digital Artery.

B.   From the mitral valve to the tricuspid valve by way of the great toe:
Through Bicuspid (Mitral) Valve Into Left Ventricle-->Aorta-->Common Iliac Artery-->External Iliac Artery-->Femoral Artery-->Posterior Tibial Artery-->Lateral Plantar Artery-->Digital Artery,Capillary Beds-->Digital Vein-->Plantar Arch-->Plantar Vein, Posterior Tibial Vein-->Femoral Vein-->External Iliac Vein-->Common Iliac Vein-->Inferior Vena Cava-->Right Atrium-->Tricuspid Valve.

11.   Trace the pathway of a carbon dioxide gas molecule in the blood from the inferior vena cava until it leaves the bloodstream. Name all structures (vessels, heart chambers, and others) passed through en route.
Inferior Vena Cava -->Right Atrium -->Tricuspid Valve -->Right Ventricle -->Pulmonary Semilunar Valve -->Pulmonary Trunk -->Pulmonary Artery -->Lobar Artery -->Pulmonary Capillary Beds In Lungs -->Air Sacs (Alveoli) Of Lungs.

12.   Trace the pathway of oxygen gas molecules from an alveolus of the lung to the right atrium of the heart. Name all structures through which it passes. Circle the areas of gas exchange.
Alveolus -->Alveolar/Capillary Walls -->Pulmonary Vein -->Left Atrium -->Bicuspid (Mitral) Valve -->Left Ventricle -->Aortic Semilunar Valve -->Aorta -->Systemic Arteries -->Capillary Beds Of Tissues -->Systemic Veins -->Superior Or Inferior Vena Cava -->Right Atrium.

13.   Most arteries of the adult body carry oxygen-rich blood, and the veins carry oxygen-depleted, carbon dioxide–rich blood. How does this differ in the pulmonary arteries and veins?
The pulmonary arteries carry oxygen-poor blood to the lungs, whereas the pulmonary veins carry oxygen-rich blood from the lungs to the heart.

14.   How do the arteries of the pulmonary circulation differ structurally from the systemic arteries? What condition is indicated by this anatomical difference?
The pulmonary arteries are more like veins anatomically. They have relatively thin walls, reflecting the fact that the pulmonary circulation is a low pressure bed.

HEPATIC PORTAL CIRCULATION
15.   What is the source of blood in the Hepatic Portal system?
Blood drained from the digestive viscera.

16.   Why is the blood carried to the liver before it enters the systemic circulation?
Blood is rich in nutrients. The liver is responsible for blood glucose, proteins, and others. The phagocytes also clean the blood of debris.

17.    The Hepatic Portal Vein is formed by the union of (a) splenic vein, which drains the spleen, pancreas, greater curvature of the stomach, distal large intestine, and (b) the superior mesenteric, which drains the small intestine and ascending colon. The gastric vein, which drains the lesser curvature of the stomach, empties directly into the Hepatic Portal Vein.

18.   Trace the flow of a drop of blood from the small intestine to the right atrium of the heart, noting all structures encountered or passed through on the way.
Capillaries of Small Intestine -->Superior Mesenteric Vein -->Hepatic Portal Vein -->Liver Sinusoids -->Hepatic Vein -->Inferior Vena Cava -->Right Atrium.
 
19.   FETAL CIRCULATION

STRUCTURE   
FUNCTION IN FETUS
FATE

Umbilical artery   
Carries O2-poor blood from the fetus to the placenta.   
Obliterated. Becomes the medial umbilical ligament.

Umbilical vein   
Carries O2-rich blood from the placenta to the fetus.   
Obliterated. Becomes the round ligament of the liver (ligamentum teres)

Ductus venosus   
Shunts blood through the fetal liver bypassing the bulk of its tissue.   
Becomes the fibrous ligamentum venosum

Ductus arteriosus   
Bypasses the fetal lungs by shunting blood from the pulmonary trunk to the aorta.   
Occludes. Becomes the ligamentum arteriosum

Foramen ovale   
Bypasses the lungs by shunting blood from the right atrium to the left atrium   
Closes. Becomes the fossa ovalis.

20.What organ serves as a respiratory/digestive/excretory organ for the fetus?    The Placenta

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The nasal and oral cavities both lead to the
a- pharynx
b- trachea
c- uvula
d- esophagus
e- larynx

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Does any body know the blood flow from ascending colon to the fingers of the left hand.

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