Exercise 24- Anatomy of blood vessels

tunica intima

(Endothelium) the innermost layer of a blood vessel

Tunica media

(Smooth muscle & Elastic fibers) The middle and thickest layer of tissue of a blood vessel wall, composed of elastic tissue and smooth muscle cells that allow the vessel to expand or contract in response to changes in blood pressure and tissue demand.

What is an artery?

A blood vessel that carries blood away from the heart

capillary permeability

Ability of substances to diffuse through capillary walls into the tissue spaces.

Trace the pathway of an oxygen gas molecule from an alveolus of the lung to the right ventricle of the heart. Name all structures through which it passes. Circle the areas of gas exchange.

Alveolus →alveolar/capillary walls→pulmonary vein→left atrium→mitral valve→left ventricle→aortic (semilunar) valve→aorta→systemic arteries→capillary beds of tissues→systemic veins→superior or inferior vena cava→right atrium→tricuspid valve→right ventricle.

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.

Aorta→ subclavian artery→ vertebral artery→ basilar artery→ posterior cerebral artery → occipital brain

Why are the walls of arteries proportionately thicker than those of the corresponding veins?

Arteries must withstand high pressure and pressure

cross-sectional views of an artery and of a vein structural details

Artery: - thick tunica media -open circular lumen Vein: -Thinner tunica media - Somewhat collapsed lumen

Ductus arteriosus - function and fate?

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

Foramen ovale - function and fate?

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

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 of the heart

Umbilical artery - function in fetus and fate?

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

Umbilical vein - function and fate?

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

Branches of the paired arteries just named cooperate to form a ring of blood vessels encircling the pituitary gland, at the base of the brain. What name is given to this communication network?

Cerebral arterial circle (circle of Willis)

Trace the blood flow for each of the following situation - From the capillary beds of the left thumb to the capillary beds of the right thumb:

Digital vein, L radial vein, L brachial vein, L axillary vein, L subclavian vein, L brachiocephalic vein, superior vena cava, R atrium, R ventricle, pulmonary trunk, pulmonary artery, lobar artery, pulmonary capillaries of the lung, lobar veins, pulmonary veins, L atrium, L ventricle, aortic arch, brachiocephalic artery, R subclavian artery, R axillary artery, R brachial artery, R radial artery, digital artery

The anterior tibial artery terminates with the ________________ artery, which is often palpated in patients with circulatory problems to determine the circulatory efficiency of the lower limb.

Dorsal pedis

Servicing the capillaries is the essential function of the organs of the circulatory system. Explain this statement.

Exchanges of nutrients, respiratory gases, and wastes can occur only through thin capillary walls. All other vessels simply feed or drain capillary beds.

The function of the ______________ is to drain digestive viscera and carry dissolved nutrients to the liver for processing.

Hepatic portal circulation

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 → right or left pulmonary artery→ lobar artery→ pulmonary capillary beds in lungs→ air sacs (alveoli) of lungs

What is the phrenic nerve?

Innervates the diaphragm. C3- C5 - critical for breathing

What two paired arteries enter the skull to supply the brain?

Internal carotids and vertebal

What organ serves as a respiratory/digestive/excretory organ for the fetus?

Placenta

What is the function of Cerebral arterial circle (circle of Willis) ?

Provides an alternate set of pathways for blood to reach brain tissue in case of impaired blood flow anywhere in the system

Ductus venosus - function and fate?

Shunts blood through the fetal liver, bypassing the bulk of its tissue. fate - Becomes the fibrous ligamentum venosus.

Veins draining the upper extremities empty into which vena cava, superior or inferior?

Superior

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

Most arteries of the adult body carry oxygen-rich blood, and the veins carry oxygen-poor 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 left heart

Why is this blood carried to the liver before it enters the systemic circulation?

This blood is rich in nutrients. The liver is the key body organ responsible for maintaining proper blood concentrations of glucose, proteins, etc. Its phagocytes also cleanse the blood of debris.

Trace the blood flow for each of the following situation - From the mitral valve to the tricuspid valve by way of the great toe:

Through mitral valve into left ventricle, aorta, common iliac artery, external iliac artery, femoral artery, posterior tibial artery, medial 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, then through tricuspid valve.

True or False Gas exchange takes place between tissue cells and blood through capillary walls

True

its smooth surface decreases resistance to blood flow

Tunica intima

bulky middle tunic; contains smooth muscle and elastin

Tunica media

From the pulmonary vein to the pulmonary artery by way of the right side of the brain:

Two pathways: (1) major pathway serves over 80% of cerebral tissue—pulmonary vein, L atrium, L ventricle, aortic arch, brachiocephalic trunk, R common carotid artery, R internal carotid artery, R middle cerebral and right anterior cerebral arteries, capillary beds, dural sinuses, internal jugular vein, brachiocephalic vein, superior vena cava, R atrium, R ventricle, pulmonary trunk, pulmonary artery; (2) pathway supplies occipital lobe and part of temporal lobe (follows pathway 1 until brachiocephalic artery), then R subclavian artery, R vertebral artery, basilar artery, R posterior cerebral artery, capillary beds (return route same as pathway 1).

Drains tissues and returns blood to the heart

Veins

What is a valve?

a flap of tissue that prevents blood from flowing backwards

two superficial veins of the arm

basilic and cephalic veins

artery that branches into radial and ulnar arteries

brachial

formed by the union of the radial and ulnar veins

brachial vein

function of veins

carry blood to the heart

an arterial trunk that has three major branches, which run to the liver, spleen, and stomach

celiac trunk

join to form the inferior vena cava

common iliac

these arteries supply the myocardium

coronary arteries

nerves the posterior thigh

deep femoral

artery on the dorsum of the foot checked after leg surgery

dorsalis ped

Fetal Circulation - The failure of two of the fetal bypass structures to become obliterated after birth can cause congenital heart disease, in which the infant's blood is improperly oxygenated. Which two structures are these?

ductus arteriosus and foramen ovale

major artery serving the tissues external to the skull

external carotid

what the external iliac artery becomes on entry into the thigh

femoral

Located in the lower limb, the _____ is the longest vein in the body

great saphenous

longest vein in the lower limb

great saphenous vein

veins draining the liver

hepatic

Which vein drains the liver

hepatic vein

artery that supplies the distal half of the large intestine

inferior mesenteric

Both the anterior and middle cerebral arteries arise from the __________________ arteries?

internal carotid

two paired arteries serving the brain

internal carotid and vertebral arteries

drains the pelvic organs

internal iliac

what is the digestive viscera?

it's an abdominal cavity

supplies the diaphragm

phrenic nerve

What does congenital mean?

present at birth

artery generally used to take the pulse at the wrist

radial

artery serving the kidney

renal artery

Sinusiods

small capillaries

supplies most of the small intestine

superior mesenter

The largest branch of the abdominal aorta supplies most of the small intestine and the first half of the large intestine.

superior mesenteric

superior mesenteric artery

supplies the small intestine

What is venous return?

the flow of blood back to the heart

Most superficial tunic

tunica externa

Tunic of capillaries

tunica intima

innermost tunic

tunica intima

Tunics of arteries and veins

tunica intima, tunica media, tunica externa

is especially thick in elastic arteries

tunica media

In the developing fetus, the umbilical (vein/artery?) carries blood rich in nutrients and oxygen to the fetus

vein

The hepatic portal vein is formed by the union of (a) ____________________, which drains the _________, _____________, ______________________________, ___________________________ and (b) ______________ which drains the _______________________________, __________________________, The _________ vein which drains the lesser curvature of the stomach, empties directly into the hepatic portal vein. ,

(a) splenic vein. spleen, pancreas, greater curvature of the stomach, and distal large intestine via the inferior mesenteric vein (B) ; superior mesenteric, the small intestine and ascending colon. The gastric vein, which drains the lesser curvature of the stomach, empties directly into the hepatic portal vein. , ,

function of elastic arteries

(pressure reservoir) conduct blood under high pressure to organs

two events in body that aid venous return

-Skeletal muscle "milking action" -Changes in thoracic cavity pressure during breathing

Why are valves present in veins but not in arteries?

-The high blood pressure in arteries propels the blood through them. -The blood pressure in veins is low and often the blood is flowing against graity. -Valves prevent back flow.

hepatic portal circulation - What is the source of blood in the hepatic portal system?

Blood drained from the digestive viscera

function and location of vertebral artery?

Supplies blood to the spinal column and brain.

What portion of the brain is served by the anterior and middle cerebral arteries?

The bulk of the cerebral hemisphere

four veins serving the leg

anterior tibial, fibular, great saphenous, posterior tibial

The largest artery in the body is?

aorta