Blood Vessels Blood is carried in a closed system of vessels that begins and ends at the heart In adult, blood vessels stretch 60,000 miles! The three.

Blood Vessels Blood is carried in a closed system of vessels that begins and ends at the heart In adult, blood vessels stretch 60,000 miles! The three major types of vessels are arteries, capillaries, and veins Arteries carry blood away from the heart (O2 rich, except pulmonary) They branch, diverge, fork Veins carry blood toward the heart (O2 poor, except pulmonary) They join, merge, converge Capillaries contact tissue cells and directly serve cellular needs

Generalized Structure of Blood Vessels
Arteries and veins are composed of three tunics – tunica interna, tunica media, and tunica externa Lumen – central blood-containing space surrounded by tunics Capillaries are composed of endothelium with sparse basal lamina

Generalized Structure of Blood Vessels
Figure 19.1b

Tunics Tunica interna (tunica intima) Tunica media
Endothelial layer that lines the lumen of all vessels Continuation w/ the endocardial lining of the heart Flat cells, slick surface In vessels larger than 1 mm, a subendothelial connective tissue basement membrane is present Tunica media Circularly arranged smooth muscle and elastic fiber layer, regulated by sympathetic nervous system Controls vasoconstriction/vasodilation of vessels

Tunica externa (tunica adventitia)
Tunics Tunica externa (tunica adventitia) Collagen fibers that protect and reinforce vessels Contains nerve fibers, lymphatic vessels, & elastin fibers Larger vessels contain vasa vasorum that nourish more external tissues of the blood vessel wall

Blood Vessel Anatomy Table 19.1

Elastic (Conducting) Arteries
Thick-walled arteries near the heart; the aorta and its major branches Large lumen allow low-resistance conduction of blood Contain elastin in all three tunics Inactive in vasoconstriction Serve as pressure reservoirs expanding and recoiling as blood is ejected from the heart

Muscular (Distributing) Arteries and Arterioles
Muscular arteries – distal to elastic arteries; deliver blood to body organs Account for most of the named structures in lab Have thickest tunica media (proportionally) of all the vessels Active in vasoconstriction Arterioles – smallest arteries; lead to capillary beds Control flow into capillary beds via vasodilation and constriction

Capillaries Capillaries are the smallest blood vessels (microscopic)
Walls consisting of a thin tunica interna, one cell thick Allow only a single RBC to pass at a time Pericytes on the outer surface stabilize their walls Tissues have a rich capillary supply Tendons, ligaments are poorly vascularized Cartilage, cornea, lens, and epithelia lack capillaries

Vascular Components Figure 19.2a, b

There are three structural types of capillaries:
Continuous Fenestrated Sinusoids

Continuous Capillaries
Continuous capillaries are abundant in the skin and muscles Endothelial cells provide an uninterrupted lining Adjacent cells are connected with tight junctions Intercellular clefts allow the passage of fluids & small solutes Brain capillaries do not have clefts (blood-brain barrier)

Fenestrated Capillaries
Found wherever active capillary absorption or filtrate formation occurs (e.g., small intestines, endocrine glands, and kidneys) Characterized by: An endothelium riddled with pores (fenestrations) Greater permeability than other capillaries

Sinusoids Highly modified, leaky, fenestrated capillaries with large lumens Found in the liver, bone marrow, lymphoid tissue, and in some endocrine organs Allow large molecules (proteins and blood cells) to pass between the blood and surrounding tissues Blood flows sluggishly (e.g. in spleen) allowing for removal of unwanted debris and immunogens

Capillary Beds A microcirculation moving from arterioles to venules
Consist of two types of vessels: Vascular shunts – metarteriole–thoroughfare channel connecting an arteriole directly with a postcapillary venule True capillaries – the actual exchange vessels Terminal arteriole feeds metarteriole which is continuous w/ the thoroughfare channel which joins the postcapillary venule

Blood Flow Through Capillary Beds
True capillaries: /bed Branch from, then return to, the capillary bed Precapillary sphincter Cuff of smooth muscle that surrounds each true capillary at the metarteriole and acts as a valve to regulate flow Blood flow is regulated by vasomotor nerves and local chemical conditions True bed is open after meals, closed between meals True bed is rerouted to skeletal muscles during physical exercise

Capillary Beds Figure 19.4a

Capillary Beds Figure 19.4b

Venous System: Venules
Venules are formed when capillary beds unite Postcapillary venules – smallest venules, composed of endothelium and a few pericytes Allow fluids and WBCs to pass from the bloodstream to tissues

Venous System: Veins Veins: Formed when venules converge
Composed of three tunics, with a thin tunica media and a thick tunica externa consisting of collagen fibers and elastic networks Accommodate a large blood volume Capacitance vessels (blood reservoirs) that contain 65% of the blood supply

Veins have much lower blood pressure and thinner walls than arteries
Venous System: Veins Veins have much lower blood pressure and thinner walls than arteries To return blood to the heart, veins have special adaptations Large-diameter lumens, which offer little resistance to flow Valves (resembling semilunar heart valves), which prevent backflow of blood Venous sinuses – specialized, flattened veins with extremely thin walls (e.g., coronary sinus of the heart and dural sinuses of the brain)

Vascular Anastomoses Merging blood vessels, more common in veins than arteries Arterial anastomoses provide alternate pathways (collateral channels) for blood to reach a given body region If one branch is blocked, the collateral channel can supply the area with adequate blood supply E.g. occur around joints, abdominal organs, brain, & heart E.g. poorly anastomized organs are retina, kidney, spleen Thoroughfare channels are examples of arteriovenous anastomoses

Physiology of Circulation: Blood Flow
Actual volume of blood flowing in a given period: Is measured in ml per min. Is equivalent to cardiac output (CO), considering the entire vascular system Is relatively constant when at rest Varies widely through individual organs

Blood Pressure (BP) Force / unit area exerted on the wall of a blood vessel by its contained blood Expressed in millimeters of mercury (mm Hg) Measured in reference to systemic arterial BP in large arteries near the heart The differences in BP within the vascular system provide the driving force that keeps blood moving from higher to lower pressure areas

Resistance Resistance – opposition to flow (friction)
Measure of the amount of friction blood encounters Generally encountered in the systemic circulation away from the heart Referred to as peripheral resistance (PR) The three sources of resistance are: Blood viscosity Total blood vessel length Blood vessel diameter

Resistance Factors: Viscosity and Vessel Length
Resistance factors that remain relatively constant are: Blood viscosity: Internal resistance to flow that exist in all fluids Increased viscosity increases resistance (molecules ability to slide past one another) Blood vessel length: The longer the vessel, the greater the resistance E.g. one extra pound of fat = 1 mile of small vessels required to service it = more resistance

Resistance Factors: Blood Vessel Diameter
Changes in vessel diameter are frequent and significantly alter peripheral resistance The smaller the tube the greater the resistance Resistance varies inversely with the fourth power of vessel radius For example, if the radius is doubled, the resistance is 1/16 as much Fluid flows slowly Fluid flows freely

Resistance Factors: Blood Vessel Diameter
Small-diameter arterioles are the major determinants of peripheral resistance Fatty plaques from atherosclerosis: Cause turbulent blood flow Dramatically increase resistance due to turbulence

Blood Flow, Blood Pressure, and Resistance
Blood flow (F) is directly proportional to the difference in blood pressure (P) between two points in the circulation If P increases, blood flow speeds up; if P decreases, blood flow declines Blood flow is inversely proportional to resistance (R) If R increases, blood flow decreases R is more important than P in influencing local blood pressure F = P/R

Systemic Blood Pressure
Any fluid driven by a pump thru a circuit of closed channels operates under pressure The fluid closest to the pump is under the greatest pressure The heart generates blood flow. Pressure results when flow is opposed by resistance…eg. Systemic Blood Pressure

Systemic pressure: Is highest in the aorta Declines throughout the length of the pathway Is 0 mm Hg in the right atrium The steepest change in blood pressure occurs in the arterioles which offer the greatest resistance to blood flow

Figure 19.5

Arterial Blood Pressure
Arterial BP reflects two factors of the arteries close to the heart Their elasticity (how much they can be stretched) The volume of blood forced into them at any given time Blood pressure in elastic arteries near the heart is pulsatile (BP rises and falls)

Systolic pressure – pressure exerted on arterial walls during left ventricular contraction pushing blood into the aorta (120 mm Hg) Diastolic pressure – aortic SL valve closes preventing backflow and the walls of the aorta recoil resulting in pressure drop lowest level of arterial pressure during a ventricular cycle

Pulse pressure – the difference between systolic and diastolic pressure Felt as a pulse during systole as arteries are expanded Mean arterial pressure (MAP) – pressure that propels the blood to the tissues Because diastole is longer than systole… MAP = diastolic pressure + 1/3 pulse pressure E.g. systolic BP = 120 mm Hg E.g. diastolic BP = 80 mm Hg MAP = 93 MAP & pulse pressure decline w/ distance from the heart At the arterioles blood flow is steady

Capillary Blood Pressure
Capillary BP ranges from 40 (beginning) to 20 (end) mm Hg Low capillary pressure is desirable because high BP would rupture fragile, thin-walled capillaries Low BP is sufficient to force filtrate out into interstitial space and distribute nutrients, gases, and hormones between blood and tissues

Venous Blood Pressure Venous BP is steady and changes little during the cardiac cycle The pressure gradient in the venous system is only about 20 mm Hg (from venules to venae cavae) vs. 60 mm Hg from the aorta to the arterioles A cut vein has even blood flow; a lacerated artery flows in spurts

Factors Aiding Venous Return
Venous BP alone is too low to promote adequate blood return and is aided by the: Respiratory “pump” – pressure changes created during breathing suck blood toward the heart by squeezing local veins Muscular “pump” – contraction of skeletal muscles surrounding deep veins “pump” blood toward the heart with valves prevent backflow during venous return Smooth muscle contraction of the tunica media by the SNS

Factors Aiding Venous Return
Figure 19.6

Maintaining Blood Pressure
Maintaining blood pressure requires: Cooperation of the heart, blood vessels, and kidneys Supervision of the brain

Maintaining Blood Pressure
The main factors influencing blood pressure are: Cardiac output (CO) Peripheral resistance (PR) Blood volume Blood pressure = CO x PR Blood pressure varies directly with CO, PR, and blood volume Changes in one (CO, PR, BV) are compensated by the others to maintain BP

Cardiac Output (CO) CO = stroke volume (ml/beat) x heart rate (beats/min) Units are L/min Cardiac output is determined by venous return and neural and hormonal controls Resting heart rate is controlled by the cardioinhibitory center via the vagus nerves Stroke volume is controlled by venous return (end diastolic volume, or EDV) Under stress, the cardioacceleratory center increases heart rate and stroke volume The end systolic volume (ESV) decreases and MAP increases

Cardiac Output (CO) Figure 19.7

Controls of Blood Pressure
Short-term controls: Are mediated by the nervous system and bloodborne chemicals Counteract moment-to-moment fluctuations in blood pressure by altering peripheral resistance Long-term controls regulate blood volume

Short-Term Mechanisms: Neural Controls
Neural controls of peripheral resistance: Alter blood distribution in response to demands Maintain MAP by altering blood vessel diameter Neural controls operate via reflex arcs involving: Baroreceptors & afferent fibers Vasomotor centers of the medulla Vasomotor fibers Vascular smooth muscle

Short-Term Mechanisms: Vasomotor Center
Vasomotor center – a cluster of sympathetic neurons in the medulla that oversees changes in blood vessel diameter Maintains blood vessel tone by innervating smooth muscles of blood vessels, especially arterioles Cardiovascular center – vasomotor center plus the cardiac centers that integrate blood pressure control by altering cardiac output and blood vessel diameter Vasomotor fibers (T1-L2) innervate smooth muscle of the arterioles Vasomotor state is always in a state of moderate constriction

Short-Term Mechanisms: Vasomotor Activity
Sympathetic activity causes: Vasoconstriction and a rise in BP if increased BP to decline to basal levels if decreased Vasomotor activity is modified by: Baroreceptors (pressure-sensitive), chemoreceptors (O2, CO2, and H+ sensitive), higher brain centers, bloodborne chemicals, and hormones

Short-Term Mechanisms: Baroreceptor-Initiated Reflexes
When arterial blood pressure rises, it stretches baroreceptos located in the carotid sinuses, aortic arch, walls of most large arteries of the neck & thorax Baroreceptors send impulses to the vasomotor center inhibiting it resulting in vasodilation of arterioles and veins and decreasing blood pressure Venous dilation shifts blood to venous reservoirs causing a decline in venous return and cardiac output Baroreceptors stimulate parasympathetic activity and inhibit the cardioacceletory center to decrease heart rate and contractile force

Declining blood pressure stimulates the cardioacceleratory center to: Increase cardiac output and vasoconstriction causing BP to rise Peripheral resistance & cardiac output are regulated together to minimize changes in BP

Baroreceptors respond to rapidly changing conditions like when you change posture They are ineffective against sustained pressure changes, e.g. chronic hypertension, where they will adapt and raise their set-point

Figure 19.8 Impulse traveling along afferent nerves from
baroreceptors: Stimulate cardioinhibitory center (and inhibit cardioacceleratory center) Sympathetic impulses to heart ( HR and contractility) Baroreceptors in carotid sinuses and aortic arch stimulated Inhibit vasomotor center CO R Rate of vasomotor impulses allows vasodilation ( vessel diameter) Arterial blood pressure rises above normal range CO and R return blood pressure to Homeostatic range Stimulus: Rising blood pressure Imbalance Homeostasis: Blood pressure in normal range Stimulus: Declining blood pressure Imbalance CO and R return blood pressure to homeostatic range Impulses from baroreceptors: Stimulate cardioacceleratory center (and inhibit cardioinhibitory center) Arterial blood pressure falls below normal range Cardiac output (CO) Baroreceptors in carotid sinuses and aortic arch inhibited Sympathetic impulses to heart ( HR and contractility) Peripheral resistance (R) Vasomotor fibers stimulate vasoconstriction Stimulate vasomotor center Figure 19.8

Short-Term Mechanisms: Chemical Controls
Blood pressure is regulated by chemoreceptor reflexes sensitive to oxygen and carbon dioxide Prominent chemoreceptors are found in the carotid and aortic bodies Response is to increase cardiac output and vasoconstriction Increased BP speeds the return of blood to the heart and lungs

Influence of Higher Brain Centers
Reflexes that regulate BP are integrated in the medulla Higher brain centers (cortex and hypothalamus) can modify BP via relays to medullary centers

Chemicals that Increase Blood Pressure
Adrenal medulla hormones – norepinephrine and epinephrine increase blood pressure NE has a vasoconstrictive action E increases cardiac output and causes vasodilation in skeletal muscles Nicotine causes vasoconstriction: stimulates sympathetic neurons and the release of large amounts of NE & E

Chemicals that Increase Blood Pressure
Antidiuretic hormone (ADH, aka vasopressin) – produced by the hypothalamus and causes intense vasoconstriction in cases of extremely low BP. It also stimulates the kidneys to conserve H2O Angiotensin II – released when renal perfusion is inadequate. The kidney’s release of renin generates angiotensin II, which causes vasoconstriction

Chemicals that Decrease Blood Pressure
Atrial natriuretic peptide (ANP) – produced by the atrium and causes blood volume and pressure to decline along with general vasodilation Nitric oxide (NO) – is a brief but potent vasodilator Inflammatory chemicals – histamine, prostacyclin, and kinins are potent vasodilators Alcohol – causes BP to drop by inhibiting ADH

Long-Term Mechanisms: Renal Regulation
Long-term mechanisms control BP by altering blood volume Baroreceptors adapt to chronic high or low BP Increased BP stimulates the kidneys to eliminate water, thus reducing BP Decreased BP stimulates the kidneys to increase blood volume and BP

Kidney Action and Blood Pressure
Kidneys act directly and indirectly to maintain long-term blood pressure Direct renal mechanism alters blood volume Indirect renal mechanism involves the renin-angiotensin mechanism

Kidney Action and Blood Pressure: Direct Renal Mechanism
Increase in BV causes an increase in BP This stimulates the kidneys to release H2O which lowers BV which in turn lowers BP

Kidney Action and Blood Pressure: Indirect Renal Mechanism
Declining BP causes the release of renin, which triggers the release of angiotensin II Angiotensin II is a potent vasoconstrictor that stimulates aldosterone secretion Aldosterone enhances renal reabsorption resulting in increased BP and BP

Kidney Action and Blood Pressure
Figure 19.9

Monitoring Circulatory Efficiency
Efficiency of the circulation can be assessed by taking pulse and blood pressure measurements Vital signs – pulse and blood pressure, along with respiratory rate and body temperature Pulse – pressure wave caused by the expansion and recoil of elastic arteries Radial pulse (taken on the radial artery at the wrist) is routinely used

Palpated Pulse Figure 19.11

Measuring Blood Pressure
Systemic arterial BP is measured indirectly with the auscultatory method A sphygmomanometer is placed on the arm superior to the elbow Pressure is increased in the cuff until it is greater than systolic pressure in the brachial artery Pressure is released slowly and the examiner listens with a stethoscope

Measuring Blood Pressure
The first sound heard is recorded as the systolic pressure The pressure when sound disappears is recorded as the diastolic pressure

Alterations in Blood Pressure
Normal BP at rest: mm Hg (systolic) & mm Hg (diastolic) Hypotension – low BP in which systolic pressure is below 100 mm Hg Hypertension – condition of sustained elevated arterial pressure of 140/90 or higher

Blood Flow Through Tissues
Blood flow, or tissue perfusion, is involved in: Delivery of oxygen and nutrients to, and removal of wastes from, tissue cells Gas exchange in the lungs Absorption of nutrients from the digestive tract Urine formation by the kidneys

Velocity of Blood Flow Blood velocity:
Changes as it travels through the systemic circulation Is inversely proportional to the cross-sectional area E.g. Fast in the aorta Slow in capillaries Fast again in the veins

Velocity of Blood Flow Figure 19.13

Autoregulation: Local Regulation of Blood Flow
Autoregulation – automatic adjustment of blood flow to each tissue in proportion to its requirements at any given point in time Blood flow through an individual organ is intrinsically controlled by modifying the diameter of local arterioles feeding its capillaries MAP remains constant, while local demands regulate the amount of blood delivered to various areas according to need

Blood Flow: Skeletal Muscles
Capillary density & blood flow is greater in red (slow oxidative) fibers than in white (fast glycolytic) fibers When muscles become active, blood flow to them increases (hyperemia) This autoregulation occurs in response to low O2 levels SNS activity increases causing an increase in NE which causes vasoconstriction of the vessels of blood reservoirs to the skin and viscera diverting blood away to the skeletal muscles

Blood Flow: Brain Blood flow to the brain is constant, as neurons are intolerant of ischemia Brain cannot store essential nutrients Very precise autoregulatory system, E.g. when you make a fist, blood supply shifts to those neurons in the cerobral motor cortex Metabolic controls – brain tissue is extremely sensitive to declines in pH, and increased carbon dioxide causes marked vasodilation Myogenic controls protect the brain from damaging changes in blood pressure Decreases in MAP cause cerebral vessels to dilate to ensure adequate perfusion Increases in MAP cause cerebral vessels to constrict so smaller vessels do not rupture MAP below 60mm Hg can cause syncope (fainting)

Blood flow through the skin:
Blood Flow: Skin Blood flow through the skin: Supplies nutrients to cells in response to oxygen need Helps maintain body temperature Provides a blood reservoir

Blood flow to venous plexuses below the skin surface:
Blood Flow: Skin Blood flow to venous plexuses below the skin surface: Varies from 50 ml/min (cold) to 2500 ml/min (hot), depending on body temperature Is controlled by sympathetic nervous system reflexes initiated by temperature receptors and the central nervous system Does this via arteriole-venule shunts located at fingertips, palms, toes, soles of feet, ears, nose, lips

Temperature Regulation
As temperature rises (e.g., heat exposure, fever, vigorous exercise): Hypothalamic signals reduce vasomotor stimulation of the skin vessels Blood flushes into capillary beds Heat radiates from the skin Sweat also causes vasodilation via bradykinin in perspiration Bradykinin stimulates the release of NO which increases vasodilation As temperature decreases, skin vessels constrict and blood is shunted to deeper, more vital organs Rosy cheeks: blood entrapment in superficial capillary loops

Blood Flow: Lungs (Think Reversal)
Blood flow in the pulmonary circulation is unusual in that: The pathway is short Arteries/arterioles are more like veins/venules (thin-walled, with large lumens) Because of this they have a much lower arterial pressure (24/8 mm Hg versus 120/80 mm Hg)

Blood Flow: Lungs The autoregulatory mechanism is exactly opposite of that in most tissues Low pulmonary oxygen levels cause vasoconstriction; high levels promote vasodilation As lung air sacs fill w/ air, capillary beds dilate to take it up

Blood Flow: Heart Small vessel coronary circulation is influenced by:
Aortic pressure The pumping activity of the ventricles During ventricular systole: Coronary vessels compress Myocardial blood flow ceases Stored myoglobin supplies sufficient oxygen During ventricular diastole, aortic pressure forces blood thru the coronary circulation During exercise, coronary blood vessels dilate in response to elevated CO2 levels

Capillary Exchange of Respiratory Gases and Nutrients
Oxygen, carbon dioxide, nutrients, and metabolic wastes diffuse between the blood and interstitial fluid along concentration gradients Oxygen and nutrients pass from the blood to tissues Carbon dioxide and metabolic wastes pass from tissues to the blood Water-soluble solutes pass through clefts and fenestrations Lipid-soluble molecules diffuse directly through endothelial membranes

Capillary Exchange of Respiratory Gases and Nutrients
Figure

Four Routes Across Capillaries
Figure

Fluid Movement: Bulk Flow
Fluid is forced out of capillary beds thru clefts at the arterial end, with most of it returning at the venous end of the bed This process determines relative fluid volume in blood stream and extracellular space

Capillary Exchange: Fluid Movements
Hydrostatic pressure is the force of a fluid pressed against a wall Direction and amount of fluid flow depends upon the difference between: Capillary hydrostatic pressure (HPc) Capillary colloid osmotic pressure (OPc)

Capillary Exchange: Fluid Movements
HPc – pressure of blood against the capillary walls: Tends to force fluids through the capillary walls (filtration) leaving behind cells and proteins Is greater at the arterial end of a bed than at the venule end HPc is opposed by interstitial fluid hydrostatic pressure (HPif) Net pressure is the difference between HPc and HPif

Colloid Osmotic Pressure
The force opposing hydrostatic pressure (HPc) OPc– created by nondiffusible plasma proteins, which draw water toward themselves (osmosis) E.g. serum albumin OPc does not vary from one end of the capillary bed to the other

Net Filtration Pressure (NFP)
Hydrostatic-Osmotic Pressure interactions determine if there is a net gain or loss of fluid from the blood, calculated as the Net Filtration Pressure (NFP) NFP – all the forces acting on a capillary bed Thus, fluid will leave the capillary bed if the NFP is greater than the net OP and vice versa

At the arterial end of a bed, hydrostatic forces dominate (fluids flow out) At the venous end of a bed, osmotic forces dominate (fluids flow in) More fluids enter the tissue beds than return blood, and the excess fluid is returned to the blood via the lymphatic system

Figure 19.16

E.g. hypovolemic shock: large scale blood loss
Circulatory Shock Circulatory shock – any condition in which blood vessels are inadequately filled and blood cannot circulate normally E.g. hypovolemic shock: large scale blood loss Blood volume decreases causing an increase in heart rate resulting in a weak pulse Vasoconstriction occurs enhancing venous return

Circulatory Shock Vascular Shock:
Blood volume is normal, but circulation is poor as a result of an abnormal expansion of the vascular bed caused by extreme vasodilation Results in rapid fall in blood pressure Most common cause is anaphylactic shock Body-wide vasodilation due to massive histamine release Neurogenic shock: failure of ANS regulation Septic shock (septicemia): severe systemic bacterial infection

KU Game Day!! No Games  But Valentine’s Day is Wednesday 

Figure 19.17

The vascular system has two distinct circulations
Circulatory Pathways The vascular system has two distinct circulations Pulmonary circulation – short loop that runs from the heart to the lungs and back to the heart Systemic circulation – routes blood through a long loop to all parts of the body and returns to the heart

Differences Between Arteries and Veins
Delivery Blood pumped into single systemic artery – the aorta Blood returns via superior and interior venae cavae and the coronary sinus Location Deep, and protected by tissue Both deep and superficial Pathways Fair, clear, and defined Convergent interconnections Supply/drainage Predictable supply Dural sinuses and hepatic portal circulation

Developmental Aspects
The endothelial lining of blood vessels arises from mesodermal cells, which collect in blood islands Blood islands form rudimentary vascular tubes through which the heart pumps blood by the fourth week of development Fetal shunts (foramen ovale and ductus arteriosus) bypass nonfunctional lungs The ductus venosus bypasses the liver The umbilical vein and arteries circulate blood to and from the placenta

Developmental Aspects
Blood vessels are trouble-free during youth Vessel formation occurs: As needed to support body growth For wound healing To rebuild vessels lost during menstrual cycles With aging, varicose veins, atherosclerosis, and increased blood pressure may arise

Pulmonary Circulation
Figure 19.18b

Systemic Circulation Figure 19.19

(b) Common carotid arteries Subclavian artery Aortic arch Coronary artery Thoracic aorta Branches of celiac trunk: Renal artery Superficial palmar arch Radial artery Ulnar artery Internal iliac artery Deep palmar arch • Left gastric artery Splenic artery Common hepatic artery Internal carotid artery Vertebral artery Brachiocephalic trunk Axillary artery Brachial artery Abdominal aorta Superior mesenteric artery Gonadal artery Common iliac artery External iliac artery Digital arteries Femoral artery Popliteal artery Inferior mesenteric artery Ascending aorta External carotid artery Anterior tibial artery Posterior tibial artery Arcuate artery Figure 19.20b

Ophthalmic artery Superficial temporal artery Basilar artery
Maxillary artery Occipital artery Facial artery Vertebral artery Internal carotid artery Lingual artery External carotid artery Superior thyroid artery Common carotid artery Larynx Thyrocervical trunk Thyroid gland (overlying trachea) Costocervical trunk Clavicle (cut) Subclavian artery Brachiocephalic trunk Axillary artery Internal thoracic artery (b) Figure 19.21b

Arteries of the Brain Anterior Cerebral arterial circle
(circle of Willis) Frontal lobe • Anterior communicating artery Optic chiasma Middle cerebral artery • Anterior cerebral artery Internal carotid artery • Posterior communicating artery Pituitary gland • Posterior cerebral artery Temporal lobe Basilar artery Pons Occipital lobe Vertebral artery Cerebellum Posterior (c) (d) Figure 19.21c,d

Common carotid arteries Vertebral artery Thyrocervical trunk Right subclavian artery Costocervical trunk Suprascapular artery Left subclavian artery Thoracoacromial artery Axillary artery Left axillary artery Subscapular artery Brachiocephalic trunk Posterior circumflex humeral artery Posterior intercostal arteries Anterior circumflex humeral artery Brachial artery Anterior intercostal artery Deep artery of arm Internal thoracic artery Common interosseous artery Descending aorta Radial artery Lateral thoracic artery Ulnar artery Deep palmar arch Superficial palmar arch Digitals (b) Figure 19.22b

Arteries of the Abdomen
Liver (cut) Diaphragm Inferior vena cava Esophagus Celiac trunk Left gastric artery Hepatic artery proper Left gastroepiploic artery Common hepatic artery Splenic artery Right gastric artery Spleen Gallbladder Stomach Gastroduodenal artery Pancreas (major portion lies posterior to stomach) Right gastroepiploic artery Superior mesenteric artery Duodenum Abdominal aorta (b) Figure 19.23b

Opening for inferior vena cava Diaphragm Inferior phrenic artery Hiatus (opening) for esophagus Middle suprarenal artery Celiac trunk Renal artery Kidney Superior mesenteric artery Lumbar arteries Gonadal (testicular or ovarian) artery Abdominal aorta Inferior mesenteric artery Median sacral artery Common iliac artery Ureter (c) Figure 19.23c

Transverse colon Celiac trunk Superior mesenteric artery Middle colic artery Intestinal arteries Left colic artery Right colic artery Inferior mesenteric artery Ileocolic artery Aorta Ascending colon Sigmoidal arteries Descending colon Ileum Left common iliac artery Superior rectal artery Sigmoid colon Cecum Rectum Appendix (d) Figure 19.23d

Arteries of the Lower Limbs
Common iliac artery Internal iliac artery Superior gluteal artery External iliac artery Deep artery of thigh Popliteal artery Lateral circumflex femoral artery Medial circumflex femoral artery Anterior tibial artery Obturator artery Femoral artery Fibular artery Posterior tibial artery Adductor hiatus Popliteal artery Dorsalis pedis artery (from top of foot) Lateral plantar artery Anterior tibial artery Medial plantar artery Plantar arch Posterior tibial artery Fibular artery (c) Dorsalis pedis artery Arcuate artery Metatarsal arteries (b) Figure 19.24b, c

brachiocephalic veins Vertebral vein Internal jugular vein
Dural sinuses Subclavian vein External jugular vein Right and left brachiocephalic veins Vertebral vein Internal jugular vein Cephalic vein Superior vena cava Brachial vein Axillary vein Basilic vein Great cardiac vein Splenic vein Hepatic veins Median cubital vein Hepatic portal vein Renal vein Superior mesenteric vein Inferior mesenteric vein Inferior vena cava Ulnar vein Radial vein Digital veins Internal iliac vein Common iliac vein External iliac vein Femoral vein Great saphenous vein Popliteal vein Posterior tibial vein Anterior tibial vein Fibular vein Dorsal venous arch Dorsal digital veins (b) Figure 19.25b

Veins of the Head and Neck
Ophthalmic vein Superficial temporal vein Facial vein Occipital vein Posterior auricular vein External jugular vein Vertebral vein Internal jugular vein Superior and middle thyroid veins Brachiocephalic vein Subclavian vein Superior vena cava (b) Figure 19.26b

Veins of the Brain Superior sagittal sinus Falx cerebri
Inferior sagittal sinus Straight sinus Cavernous sinus Junction of sinuses Transverse sinuses Sigmoid sinus Jugular foramen Right internal jugular vein (c) Figure 19.26c

Veins of the Upper Limbs and Thorax
Internal jugular vein External jugular vein Brachiocephalic veins Left subclavian vein Right subclavian vein Superior vena cava Axillary vein Azygos vein Accessory hemiazygos vein Brachial vein Cephalic vein Hemiazygos vein Basilic vein Posterior intercostals Inferior Median cubital vein vena cava Ascending lumbar vein Median antebrachial vein Basilic vein Ulnar vein Cephalic vein Deep palmar venous arch Radial vein Superficial palmar venous arch Digital veins (b) Figure 19.27b

Veins of the Abdomen Inferior phrenic vein Hepatic veins
Inferior vena cava Left suprarenal vein Right suprarenal vein Renal veins Left ascending lumbar vein Right gonadal vein Lumbar veins Left gonadal vein Common iliac vein External iliac vein Internal iliac vein (b) Figure 19.28b

Veins of the Abdomen Hepatic veins Gastric veins Liver Spleen
Inferior vena cava Hepatic portal vein Splenic vein Right gastroepiploic vein Inferior mesenteric vein Superior mesenteric vein Small intestine Large intestine Rectum (c) Figure 19.28c

Fibular (peroneal) vein
Common iliac vein Internal iliac vein External iliac vein Inguinal ligament Femoral vein Great saphenous vein (superficial) Great saphenous vein Popliteal vein Popliteal vein Anterior tibial vein Fibular (peroneal) vein Fibular (peroneal) vein Small saphenous vein (superficial) Anterior tibial vein Posterior tibial vein Dorsalis pedis vein Plantar veins Dorsal venous arch Plantar arch Metatarsal veins Digital veins (c) (b) Figure 19.29b, c

Blood Vessels Blood is carried in a closed system of vessels that begins and ends at the heart In adult, blood vessels stretch 60,000 miles! The three.

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Blood Vessels Blood is carried in a closed system of vessels that begins and ends at the heart In adult, blood vessels stretch 60,000 miles! The three.

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Presentation on theme: "Blood Vessels Blood is carried in a closed system of vessels that begins and ends at the heart In adult, blood vessels stretch 60,000 miles! The three."— Presentation transcript:

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