Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 13 Lecture Slides

Chapter 13-Blood Vessels Functions 1. Carry blood 2. Exchange nutrients, waste products, gases within tissues 3. Transport substances 4. Regulate blood pressure 5. Direct blood flow to tissues

Vessel Structures Arterties: - carry blood away from heart - thick with a lot of elastic Veins: - carry blood toward heart - think with less elastic Capillaries: exchange occurs between blood and tissue fluids

Blood Flow Blood flows from arteries into arterioles Arterioles into capillaries Capillaries into venules Venules to small veins Veins return to heart

Blood Vessel Walls Tunica intima: - innermost layer - simple squamous Tunica media: - middle layer - smooth muscle with elastic and collagen Tunica adventitia: - outermost layer - connective tissue

Types of Arteries Elastic arteries: - largest in diameter - thickest walls - Ex. Aorta and pulmonary trunk Muscular arteries: - medium to small size - thick in diameter - contain smooth muscle cells - can control blood flow to body regions

Capillaries Blood flows from arterioles into capillaries Capillaries branch to form networks Blood flow is regulated by smooth muscle cells, precapillary sphincters

Types of Veins Blood flows from capillaries into venules Blood flows from venules into small veins All 3 tunics are present in small veins Medium sized veins: collect blood from small veins and deliver to large viens Large veins: contain valves

Blood Vessels of Pulmonary Circulation Pulmonary circulation: blood vessels that carry blood from right ventricle to lungs and back from left atrium of heart Pulmonary trunk: blood pump from right ventricle towards lung Pulmonary veins: exit lungs and carry O 2 rich blood to left atrium

Parts of Aorta Ascending: passes superiorly from left ventricle Aortic Arch: 3 major arteries which carry blood to head and upper limbs Descending: extends through thorax and abdomen to pelvis

Thoracic: part of descending aorta that extends through thorax to diaphragm Abdominal: descending aorta that extends from diaphragm where it divides at common iliac arteries

Arteries of Head and Neck Branches of aortic arch: - brachiocephalic artery - left common carotid artery - left subclavian Brachiocephalic artery: - first branch off aortic arch - supplies blood to right side of head and neck

Left common carotid artery: - 2 nd branch off aortic arch - supplies blood to the left side of head and neck Left subclavian artery: - 3 rd branch off aortic arch - supplies blood to left upper limbs

Right common carotid artery: - branches off brachiocephalic artery - supplies blood to right side of head and neck Right subclavian artery: - branches off brachiocephalic artery - supplies blood to right upper limbs

Arteries of Upper Limbs Axillary arteries: - continuation of subclavian - supply blood deep in clavicle Brachial arteries: - continuation of axillary - where blood pressure measurements are taken

Ulnar arteries: - branch of brachial artery - near elbow Radial arteries: - branch of brachial artery - supply blood to forearm and hand - pulse taken here

Figure 13.11

Arteries off Abdominal Aorta Celiac trunk arteries: supply blood to stomach, pancreas, spleen, liver, upper duodenum Superior mesenteric arteries: supply blood to small intestines and upper portion of colon Inferior mesenteric arteries: supply blood to colon

Renal arteries: supply blood to kidneys Hepatic arteries: supply blood to liver Testicular arteries: supply blood to testes Ovarian arteries: supply blood to ovaries

Inferior phrenic arteries: supply blood to diaphragm Lumbar arteries: supply blood to lumbar vertebra and back muscles

Figure 13.7c

Arteries of Pelvis Common iliac arteries: - branches from abdominal aorta - divides into internal iliac arteries External iliac arteries: - division of common iliac artery - supply blood to lower limbs Internal iliac arteries: - division of common iliac - supply blood to pelvic area

Arteries of Lower Limbs Femoral arteries: supply to thigh Popliteal arteries: supply blood to knee Anterior and posterior arteries: supply blood to leg and foot Fibular arteries: supply blood to lateral leg and foot

Figure 13.13

Veins Superior vena cava: - returns blood from head, neck, thorax, and right upper limbs - empties into right atrium of heart Inferior vena cava: - returns blood from abdomen, pelvis, lower limbs - empties into right atrium of heart

Veins of Head and Neck External jugular vein: - drain blood from head and neck - empties into subclavian veins Internal jugular vein: - drain blood from brain, face, neck - empty into subclavian veins

Subclavian veins: forms brachiocephalic veins Brachiocephalic veins: join to form superior vena cava

Veins of Upper Limbs Brachial veins: empty into axillary vein Cephalic veins: empty into axillary vein and basilic vein Median cubital veins: - connects to cephalic vein - near elbow

Veins of Thorax Right and left brachiocephalic veins: drain blood from thorax into superior vena cava Azygos veins: drain blood from thorax into superior vena cava Internal thoracic veins: empty into brachiocephalic veins

Posterior intercostal veins: - drain blood from posterior thoracic wall - drains into azygos vein on right side Hemiazygos vein: receives blood from azygos vein of left side

Veins of Abdomen and Pelvis Common iliac vein: - formed from external and internal iliacs - empty into inferior vena cava External iliac vein: - drains blood from lower limbs - empty into common iliac vein

Internal iliac vein: - drains blood from pelvic region - empties into common iliac vein Renal vein: drains blood from kidneys

Hepatic Portal System Liver is a major processing center for substances absorbed by intestinal tract. Portal system: - vascular system that begins with capillaries in viscera and ends with capillaries in liver - uses splenic vein and superior mesenteric vein

Veins of Lower Limbs Femoral veins: drain blood from thigh and empty into external iliac vein Great saphenous veins: drain from foot and empty into femoral vein Popliteal veins: drain blood from knee and empty into femoral vein

Figure 13.14

Blood Pressure What is it? measure of force blood exerts against blood vessel walls Systolic pressure: contraction of heart Diastolic pressure: relaxation of heart Normal is 120/80

Pulse Pressure What is it? - difference between systolic and diastolic pressure - Ex. 120 for systolic 80 for diastolic pulse pressure is 40 mm Hg - pulse pressure points can be felt near large arteries

Capillary Exchange Most exchange across capillary wall’s occurs by diffusion Blood pressure, capillary permeability and osmosis affect movement of fluids across capillary walls. Net movement of fluid from blood into tissues Fluid gained in tissues is removed by lymphatic system

Local Control of Blood Flow Local control achieved by relaxation and contraction of precapillary sphincters Sphincters relax blood flow increases Precapillary sphincters controlled by metabolic needs of tissues Concentration of nutrients also control blood flow Blood flow increases when oxygen levels decrease

Nervous and Hormonal Control of Blood Flow Vasomotor center: - sympathetic division - controls blood vessel diameter Vasomotor tone: - state of partial constriction of blood vessels - increase causes blood vessels to constrict and blood pressure to go up Epinephrine and norepinephrine (adrenal medulla) alter blood vessel diameter

Baroreceptor Reflexes Baroreceptor reflexes activate responses to blood pressure in normal range Baroreceptors respond to stretch in arteries due to increased pressure Located in carotid sinuses and aortic arch Change peripheral resistance, heart rate, stroke volume in response to blood pressure

Chemoreceptor Reflex Chemoreceptors are sensitive to changes in blood oxygen, carbon dioxide, and pH Chemoreceptors are located in carotid bodies and aortic bodies which lie near carotid sinuses and aortic arch They send action potentials along sensory nerve to medulla oblongata

Adrenal Medullary Mechanism 1.Stimuli increase sympathetic stimulation to adrenal medulla 2.Adrenal medulla secretes epinephrine and norepinephrine into blood 3.This causes increased heart rate and stroke volume and vasoconstriction 4.Vasodilation of blood vessels in skeletal and cardiac muscle

Renin-Angiotensin-Aldosterone Mechanism 1.Reduce blood flow causes kidneys to release renin 2.Renin acts on angtiotensinogen to produce angiotensin I 3.Angiotensin-converting enzyme converts angiotensin I to angtiotensin II 4.Angiotensin II causes vasoconstriction 5.Angiotensin II acts on adrenal cortex to release aldosterone

6. Aldosterone acts on kidneys causes them to conserve sodium and water 7. Result less water lost in urine and blood pressure maintained

Antidiuretic Hormone Mechanism 1.Nerve cells in hypothalamus release antidiuretic hormone (ADH) when concentration of solutes in plasma increases or blood pressure decrease 2.ADH acts of kidneys and they absorb more water (decrease urine volume) 3.Result is maintain blood volume and blood pressure

Other Information Arteriosclerosis: makes arteries less elastic Atherosclerosis: - type of arteriosclerosis - from deposit of materials in artery walls (plaque) Factors that contribute to atherosclerosis: lack of exercise, smoking, obesity, diet high in cholesterol and trans fats, some genetics