Chapter 19 - The Cardiovascular System and Blood Vessels

Question 1

Pathway of Blood

Answer 1

Leaves ventricles of heart and flows into large arteries; vestries into large arteries, then moves into smaller arteries which branch into arterioles they feed into the capillary beds from capillaries to venues (smallest veins); larger and larger veins which eventually empties into the heart. Blood vessels in adults stretch out about 60K miles

Question 2

Oxygenation (S&P)

Answer 2

1. Systemic circulation – rooting blood though a long loop to all parts of the body before returning it to the heart
2. Pulmonary circulation – short loop from the heart to the lung and back to the heart

Question 3

Layers of Vessel Walls: Tunica Intima

Answer 3

Inner most layer of the blood vessels; intimate contact with blood in the lumen, it contains the endothelium and it’s the thinnest layer of the 3

a. Endothelium – specialized simple squamous; and lines the lumen of all vessels; its continuous with the endocardio lining of the heart
b. Subendothelial layer – found in vessels that are > 1 mm in diameter; consists of basement membrane and loose connective tissue which supports the endothelium

Question 4

Layers of Vessel Walls: Tunica Media

Answer 4

Middle; and mostly circularly arranged smooth muscle cells and sheets of elastin; its regulated by the sympathic basal motor nerve fibers of the autonomic nerve system (ANS); the bulkiest
a. Internal and external elastic lamina – found in muscular arteries ONLY; thin layer of sub endothelia connective tissue which is interlaced with a number of circularly arranged elastic bands; found on each side of the tunica media and they’re swish cheese like

Question 5

Layers of Vessel Walls: Tunica Externa

Answer 5

Outer most layer of blood vessels and its composed largely of woven collagen fibers that protect, reinforce and anchor it; infiltrated with nerve fibers, lymphatic nerve vessels and in large veins it contains elastin fibers
a. Vasa vasorum – system of tiny blood vessels that are found in large vessels; the vessels of the vessels, nourish the external tissues of the blood vessel walls, the inner most layers receive nutrients from the lumen

Question 6

Arterial System: Elastic Arties

Answer 6

AKA conducting arteries, contain more elastin, substantial amounts of smooth muscle and relatively inactive in vaso constriction

 1. Function – conduct blood from the heart to medium sized arteries; thick walled and found near the heart 
 2. Structure – largest in diameter and they arrange from 1.0 mm – 1.5 cm

Question 7

Arterial System: Muscular Arteries

Answer 7

AKA distributing arteries, part after the elastic arteries

 1. Function – deliver blood to specific body organs; they account for most of the named arteries 
 2. Structure – internal diameter, from 1.0 cm – 6.0mm; thickest tunica media; contains more smooth muscle than elastic and have less elastic tissue; more active in vaso constriction

Question 8

Arterial System: Arterioles

Answer 8

Smallest

 1. Function – determine the blood flow into capillary beds; respond to neural, hormonal and chemical signals 
 2. Structure – lumen diameter can range from 0.3 mm – 10.0 micrometers

Question 9

Capillaries

Answer 9

Capillaries – microscopic and the smallest blood vessels
A. Function – act as back allies and driveways which provide direct access to every cell in the body (where nutrients are exchanged); exchange of materials between blood and interstitial fluid
B. Structure
1. Pericytes – spider shaped, smooth muscle like cells, they stabilize the capillary wall and help control capillary permeability

Question 10

Capillary Beds

Answer 10

Interweaving networks which carry blood flow from and arteriole to a venal (microcirculation); has 2 vessels (vascular shunt and true capillaries)

 1. Terminal arteriole – feeds the capillary bed blood from the vessels  
 2. Postcapillary venule – drains the bed 
 3. True capillaries – surround the shunt; quantity from 10-100 per capillary bed, branch off the metarteriole and return to the thoroughfare channel; actual exchange vessels   
     a. Precapillary sphincter – cuff of smooth muscle fibers which surrounds the root of each true capillary at the metarteriole and they act as valves and they regulate blood flow into the capillary 
 4. Vascular shunt – runs though the true capillaries; when artillery blood mixes with Venus blood; vascular shunt is created by a short vessels that connects the arterial and venal at opposite ends of the bend  
     a. Metarteriole – vessel; found between the arterial and the capillary 
     b. Thoroughfare channel – between the capillary bed and the venal; joins the post capillary venules

Question 11

Venules

Answer 11

1. Function – extremely porous; fluid and white blood cells being able to move through their walls; allowing white blood cells and fluid to leak out
2. Structure – formed after the capillaries unite; the smallest venules consist of endothelium and pericytes; larger venules have one or two layers of smooth muscle cells and a very thin tunica externa

Question 12

Veins

Answer 12

Formed when venules join

 1. Function – blood reservoirs; where excess blood collects, contains up to 65% of the body’s blood supply  
 2. Structure – 3 distinct tunics, walls are always thinner and lumen are larger than arteries; little smooth muscle in the tunica media, tunica externa – thick longitudinal collagen fibers and elastic networks, vensous valves – formed from folds of the tunica intima   
     a. Venous valves – semilunar valves in structure and in function; formed from folds of the tunica intima; more abundant in limbs when it is opposed by gravity

Question 13

Major Veins of the Body: Pulmonary Circulation

Answer 13

Pulmonary circulation – function to bring blood into contact with the lungs so gas can be exchanged

 a. Pulmonary veins – complete the pulmonary circuit by unloading blood into the left atrium 
 b. Pulmonary artery – from the from heart to lungs

Question 14

Major Veins of the Body: Systemic Circulation

Answer 14

Functional blood supply to all body tissues while carrying away carbon dioxide and wastes

Question 15

Major Veins of the Body: Systemic Circulation - Superior Vena Cava

Answer 15

Systemic blood found draining from all areas superior to the diaphragm and it’s formed by the union of the right and left brachiocephalic veins; empties its contents into the right atrium of the heart

i. Brachiocephalic veins – 2 right and left; are formed by the union of the internal jugular vein and the subclavian vein
ii. Internal jugular veins – paired; receive the bulk of blood draining form the brain
iii. Subclavian veins – paired; vessel after the brachiocephalic vein, it continues until the first rib, after the first rib the vein changes name

Question 16

Major Veins of the Body: Systemic Circulation - Inferior Vena Cava

Answer 16

Returns blood to the right side of the heart from all body regions below the diaphragm
i. Common iliac veins – form the inferior vena cava at L5; they drain the lower veins

Question 17

Major Veins of the Body: Systemic Circulation - Veins of the Brain

Answer 17

i. Superior and inferior sagittal sinuses – found in the falx cerebri; drains into the straight sinus, both empty into the transverse sinuses
ii. Straight and transverse sinuses – meet at a region confluence of sinuses
iii. Sigmoid sinuses and internal jugular veins – sigmoid sinuses are S shaped and they become the internal jugular veins as they leave the skull though the jugular foreman

Question 18

Major Veins of the Body: Systemic Circulation - Veins of the Head and Neck

Answer 18

i. Facial veins – drain the nose and the upper lip area
ii. Occipital veins and external jugular veins – drains the superficial scalp and the face structures; occipital veins drains the occipital region of the head

Question 19

Major Veins of the Body: Systemic Circulation - Veins of the Thorax

Answer 19

i. Azygos vein – located against the right side of the vertebral column and it originates in the abdomen from the right acceding lobar vein
ii. Intercostal veins – posterior aspect and they drain the chest muscles

Question 20

Major Veins of the Body: Systemic Circulation - Veins of the Upper Limbs

Answer 20

i. Radial and ulnar veins – deep veins of the forearm and they unite to from the brachial vein
ii. Brachial veins – veins of the arms; they become the axillary veins as it enters the axilla
iii. Cephalic and basilic veins – cephalic – travels superiorly up the radius and to the later superficial aspect of the arm to the shoulder where it runs to join the axillary vein; basilic – found on the posterior medial aspect of the arm, it crosses the elbow and joins the brachial vein in forming the axillary vein
iv. Median cubital veins – connects basilica and cephalic veins, most commonly used from vena punctures
v. Axillary veins –formed by the brachial and cephalic and it becomes the sub clavian rib at the first rib

Question 21

Major Veins of the Body: Systemic Circulation - Veins of the Abdomen

Answer 21

i. Suprarenal veins – right drains the adrenal gland on the right side and it empties into the inferior vena cava however the left drains into the renal vein
ii. Renal veins – drains the kidneys
iii. Gonadal (testicular and ovarian) veins – right gonadal drains the right directly into the inferior vena vaca; the left drains into the renal vein which eventually takes it to the inferior vena cava

Question 22

Major Veins of the Body: Systemic Circulation - Hepatic Portal System

Answer 22

i. Hepatic portal vein – short and it begins at L2 it unites the 1st and 2nd capillary beds (stomach and intestine) (2nd – found in liver)
ii. Superior mesenteric vein – drains the entire small intestine, part of the large intestine (ascending and transverse) and stomach
iii. Splenic vein – collects blood from the spleen also from some parts of the stomach and the pancreases and it joins the SMV and help from the hepatic portal vein
iv. Inferior mesenteric vein – drains the distal portions of the large intestine and the rectum and joins the splenic vein just before the vessel units with the SMV
v. Hepatic veins – 3 veins – right, left and middle and they carry blood from the liver to the inferior vena cava
vi. Gastric and ileocolic veins – drain the stomach and the ileocolic region

Question 23

Major Veins of the Body: Systemic Circulation - Veins of the Pelvis

Answer 23

i. Internal iliac veins – join the external iliac vein to form the common iliac vein
ii. External iliac veins – formed by the femoral vein and joins the internal iliac vein to form the common iliac vein

Question 24

Major Veins of the Body: Systemic Circulation - Veins of the Lower Limbs

Answer 24

i. Fibular veins – peroneal veins and they’re a branch of the popliteal vein
ii. Anterior and posterior tibial veins – anterior – superior continuation of the dorsalis pedis vein; posterior – ascends deep in the calf muscles and it revives the fibular vein
iii. Popliteal veins – formed by the dorsalis pedis vein and the posterior tibial vein (found in the back of the knee)
iv. Femoral veins – drain the deep structures of the thigh
v. Great saphenous vein – very superficial vein and is the longest vein of the body; it travels superiorly along the medal aspect of the leg to the thigh; it empties its contents to the femoral vein distal to the inguinal ligament

Question 25

Major Arteries of the Body: Pulmonary Circulation

Answer 25

Pulmonary circulation – bring blood into close contact with aveoli with the lungs for gas exchange a. Pulmonary trunk – after the right ventricle; divides into pulmonary arteries, rooting blood into pulmonary arteries b. Pulmonary arteries – segment found after pulmonary trunk; right and left – responsible for taking blood to the lungs c. Pulmonary veins – complete the circuit and they unload oxygenated blood into the left atrium

Question 26

Major Arteries of the Body: Systemic Circulation

Answer 26

Provide functional blood supply to all body tissues; delivers oxygen and nutrients

Question 27

Major Arteries of the Body: Systemic Circulation - Aorta

Answer 27

Aorta – largest; about the size of a garden hose at the region where it exits the heart, 2cm-2.5 cm the wall is about 2mm thick i. Ascending aorta – first portion, runs posteriorly and to the right of the pulmonary trunk; about 5 cm long before it curves left and it becomes aortic arch ii. Aortic arch – deep to the sternum; it begins and ends at the sternal angle (T4) A. Brachiocephalic trunk – passes superiorly under the right sternal-clavicular joint then it branches 1. Right common carotid artery – supplies the right side of head and neck and it branches to form the internal and external carotid arteries 2. Right subclavian artery – neck and right upper limb; axillary and vertebral right artery B. Left common carotid artery – left side of head and neck; left external and internal carotid arteries C. Left subclavian artery – left side of the neck and left upper limb; axillary and vertebral left artery iii. Descending aorta – aka thoracic; runs along the anterior spine from T5-T12; supplies the thoracic wall and the viscera of the thorax before piercing the diaphragm iv. Abdominal aorta – after descending aorta; found in abdominal cavity; supplies the walls of the abdomen and viscera ends at L4 where it splits into the common iliac arteries v. Common iliac arteries – supply the pelvis and the lower limbs

Question 28

Major Arteries of the Body: Systemic Circulation - Head and Neck

Answer 28

i. Common carotid arteries – divide into 2 major branches; right arises from the brachiocephalic trunk, the left is the second branch off the aortic arch; and they ascends through the lateral neck and divide at the superior boarder of the larynx ii. External and internal carotid arteries – supply most tissue of the head except the brain and the orbits; external sends branches to the thyroid, larynx, tongue, skin and muscles of anterior face and posterior scalp. Internal – supply orbits and > 80% of the cerebrum, it enters the skull though the carotid canals and give off branches (althalmic artery) and divides into the anterior and middle cerebral arteries iii. Facial arteries – branch of the external and supply the skin and muscles of the anterior face iv. Occipital arteries – supply the posterior scalp v. Superficial temporal arteries – found as the terminal part of the external carotid; supply the prorated gland and most of the scalp

Question 29

Major Arteries of the Body: Systemic Circulation - Brain

Answer 29

i. Vertebral arteries – branches from the subcalvian arteries at the root of the neck and they ascend though the foreman of the transverse processes of the cervical vertebra to enter the skull though the foreman magnum; give off branches to the vertebra and to cervical spinal cord, within the cranium the right and left come together to give rise to the basilar artery ii. Basilar artery – formed from right and left vertebral arteries; ascends along the anterior aspect of the brain stem and gives off branches to the cerebellum, pons and inner ear iii. Posterior cerebral arteries – divisions from the basilar artery and found at the pons midbrain boarder; the supply the occipital lobes and the inferior parts of the temporal lobes iv. Circle of Willis – 2 posterior and 1 anterior communicating arteries; encircles the pituitary gland and optic chasma and it unites the brains anterior and posterior blood supply, helps equalize pressures and provides alternate roots for blood incase blood is included on one side A. Anterior and posterior communicating arteries – help connect the brains blood supply

Question 30

Major Arteries of the Body: Systemic Circulation - Thorax

Answer 30

i. Internal thoracic arteries – aka internal mammary arteries – arise from the subclavian arteries and they supply most of the anterior thorax

Question 31

Major Arteries of the Body: Systemic Circulation - Upper Limbs

Answer 31

i. Axillary arteries – run through the axilla and give off branches to the axilla, also to the chest wall and shoulder girdle ii. Brachial arteries – continuation of axillary arteries; run down the medial aspect of the humorous, they supply the anterior flexor muscles of the arm they split to form the radial and ulnar arteries iii. Radial and ulnar arteries – radial – supply the lateral muscles of the forearm, wrist, thumb and index fingers; ulnar – supply the medal aspect of the forearm and fingers 3-5 and the medial part of the index finger

Question 32

Major Arteries of the Body: Systemic Circulation - Abdomen

Answer 32

i. Celiac trunk – very large unpaired branch of the abdominal aorta and it divides into 3 major branches a. Gastric – part of stomach (left lesser curvature) and inferior esophagus b. common hepatic – gives branches to the stomach, duodenum and pancreases c. splenic arteries – runs deep to the stomach and sends branches to the pancreases and to the stomach (right greater curvature) it terminates at the spleen d. right gastric – part of the stomach (right lesser curvature) and common hepatic artery ii. Superior mesenteric artery – large unpaired branch at L1; below the celiac trunk, supplies pancreases, small intestine and some of large intestine (appendix, cecum, ascending colon, and part of the transverse) a. Ileocolic artery – supplies the ileocolic region b. Renal, suprarenal, and gonadal (testicular /ovarian) arteries – supply region according to name c. Inferior mesenteric artery – final major branch; unpaired, arises from L3, serves distal part of large intestine from the midpoint of the transverse colon down to the mid rectal region

Question 33

Major Arteries of the Body: Systemic Circulation - Pelvis

Answer 33

i. Internal and external iliac arteries – internal – paired that run into the pelvis; supply pelvic wall and the versa of the pelvis (bladder, rectum, uterus, vagina, prostate, ductus deferens), gluteal muscles, adductor muscles, external genitalia and perineum. External – lower limbs and gives branches to the anterior abdominal wall this becomes femoral arterie

Question 34

Major Arteries of the Body: Systemic Circulation - Lower Limbs

Answer 34

i. Femoral – several branches to the thigh and becomes the poplieteal artery after passing though the adductor hiatus ii. Popliteal arteries – supplies knee region; splits into anterior and posterior tibial arteries iii. Anterior tibial – runs anterior compartment of the leg and supplies the extensor muscles along the way, at the ankle it becomes the dorsals pedis artery iv. Posterior tibial – courses though the posterioral medial part of the leg and it supplies the flexor muscles v. Fibular arteries – poroneal – branch of the posterior tibial; supplies the lateral muscles of the leg