bio 116 chap19

Identify the branches of the aortic arch and name the areas each serves.

brachiocephalic trunk branches to form the right subclavian artery and right common carotid artery. left common carotid artery supplies the left side of neck and head. left subclavian artery has same distribution patterns as the right subclavian artery. right subclavian artery branches into the internal thoracic artery supplying pericardium and anterior wall of the chest a, branches into vertebral artery as well. that provides blood to the brain and spinal cord. after crossing the first rib the subclavian is called the axillary artery, crosses the axilla to enter the arm where it becomes the brachial artery which supplies blood to the upper limb. the brachial artery divides into the radial artery which follows the radius and the ulnar artery which follows the ulna to the wrist. at the wrist the radial and ulnar arteries fuse to form the superficial and deep palmar arches which supply blood to the hand and to the digital arteries of the thumb and fingers.

Describe the role of chemoreceptor reflexes in adjusting cardiovascular activity.

the chemoreceptor reflexes respond to changes in carbon dioxide, oxygen, or pH levels in blood and CSF. stimulation of these chemoreceptors triggers coordinated adjustments in cardiovascular and respiratory activity.

Explain the body's response to blood loss.

the entire cardiovascular system makes adjustments to maintain blood pressure and restore blood volume. the immediate problem is the maintenance of adequate BP and peripheral blood flow. long-term problem is the restoration of normal BV, mechanisms can cope with blood losses ~30% of total BV. shock is an acute cardiovascular crisis marked by low BP and inadequate peripheral blood flow. severe and potentially fatal signs and symptoms develop as vital tissues become starved for oxygen and nutrients.

Explain the roles of pressure, resistance, and venous return in cardiac output.

•Blood pressure Pressure within the cardiovascular system as a whole, Arterial pressure is much higher than venous pressure, Must push blood greater distance through smaller vessels. •resistance Force that opposes movement. Peripheral resistance, Resistance of the arterial system as a whole, Increases as vessels get smaller. •Venous return Amount of blood arriving at the right atrium each minute, On average, equal to the cardiac output.

Describe the factors that determine blood flow.

•Cardiac output •Central regulation •Peripheral resistance •Venous return

Describe the factors that influence total peripheral resistance.

vascular resistance, blood viscocity, and turbulence

Distinguish between vasculogenesis and angiogenesis.

vasculogenesis is the formation of new vessels by hemangioblasts and precursor andothelial cells. angiogenesis is the growth of new blood vessels from preexisting vessels.

Explain how the cardiovascular system responds to the demands of exercise.

vasodilation occurs, peripheral resistance drops, and blood flow increases. the venous return increases as skeletal muscle contractions squeeze blood along the peripheral veins. at the same time, each inhalation creates a negative pressure in the thoracic cavity that pulls blood into the venae cavae from their branches. this mechanism is called the respiratory pump. cardiac output increases, primarily because of the increased venous return.

Explain the hormonal regulation of blood pressure and blood volume.

when blood pressure and volume decrease below normal, the immediate response is the release of epinephrine and norepinephrine from the adrenal medullae, stimulating cardiac output and peripheral vasoconstriction. other important hormones in the long-term response is antidiuretic hormone, angiotensin, erythropoietin, and aldosterone. excessive blood volume triggers a response through its effects on the walls of the heart. when the heart walls are abnormally stretched during diastole, cardiac muscle cells release natriuretic peptides.

Discuss the movement of fluids between capillaries and interstitial spaces.

when hydrostatic pressure is greater, fluid moves from capillaries to interstitial space. when osmotic pressure is greater, fluid flows from interstitial space to capillaries.

Distinguish among the types of blood vessels on the basis of their structure and function.

1.Arteries •Elastic arteries Large vessels close to the heart that stretch and recoil when heart beats, Include pulmonary trunk, aorta, and branches •Muscular arteries Medium-sized arteries, Distribute blood to skeletal muscles and internal organs 2.​Arterioles Poorly defined tunica externa, Tunica media is only 1-2 smooth muscle cells thick 3.​Capillaries Only blood vessels to allow exchange between blood and interstitial fluid, Very thin walls allow easy diffusion 4.​Venules Small veins, Those smaller than 50 µmlack a tunica media and resemble expanded capillaries, Collect blood from capillaries 5.​Veins •Medium-sized veins Range from 2 to 9 mm in internal diameter, Thin tunica media with smooth muscle cells and collagen fibers, Thickest layer is tunica externa with longitudinal collagen and elastic fibers •Large veins Contain all three vessel wall layers, Thin tunica media surrounded by thick tunica externa, Include superior and inferior venae cavae and tributaries

Distinguish between the pulmonary and systemic circuits, and identify afferent and efferent blood vessels.

1.Pulmonary circuit •To and from gas exchange surfaces in the lungs Right atrium (entry chamber) Collects blood from systemic circuit To right ventricle to pulmonary circuit Pulmonary circuit Pulmonary arteries to pulmonary capillaries to pulmonary veins 2.​Systemic circuit •To and from rest of body Left atrium •Receives blood from pulmonary circuit •To left ventricle to systemic circuit ​Systemic circuit •Systemic arteries to systemic capillaries to systemic veins •Arteries (carry blood away from the heart) Also called efferent vessels •Veins (carry blood to the heart) Also called afferent vessels

Explain central regulation, autoregulation, and baroreceptor reflexes in response to changes in blood pressure and blood composition.

Central regulation involves both neural and endocrine mechanisms. Autoregulation involves local changes in the pattern of blood flow within capillary beds. These changes are due to precapillary sphincters that open and close in response to chemical changes in the IF. baroreceptor reflexes respond to changes in blood pressure. arterial baroreceptors are located in the carotid sinuses and the aortic arch

Describe the pathways taken by oxygenated blood and deoxygenated blood in the systemic circuit.

Systemic circulation carries oxygenated blood from the left ventricle, through the arteries, to the capillaries in the tissues of the body. From the tissue capillaries, the deoxygenated blood returns through a system of veins to the right atrium of the heart.

Describe the venous system, and indicate the distribution of blood within the cardiovascular system.

The venous system has low pressures and contains almost two-thirds of the body's blood volume. •Valves Folds of tunica intima projecting from vessel wall and pointing in the direction of blood flow Ensure one-way flow of blood toward heart •Contraction of skeletal muscles •Venoconstriction

Identify the major arteries and veins of the pulmonary circuit, and name the areas each serves.

circuit begins at the right ventricle and ends at the left atrium. arteries and veins transport blood between the heart and the lungs

Describe the differences between fetal and adult circulation patterns, identify changes in blood flow patterns at birth, and list common congenital heart problems.

fetal blood flows to the placenta through a pair of umbilical arteries. blood returns from the placenta in the single umbilical vein bringing oxygen and nutrients to the fetus. when the placental connection is broken at birth, blood stops flowing in the umbilical vessels and they soon degenerate. ventricular septal defect openings in the interventricular septum that separate the right and left ventricles. patent foramen ovale and patent ductus arteriosus creates a right-to-left-shunt. tetralogy of fallot a complex group of heart and circulatory defects that affect 0.10% of newborn infants. atrioventricular septal defect both atria and ventricles are incompletely separated. transposition of the great vessels, the aorta is connected to the right ventricle instead of to the left ventricle

Identify the major arteries and veins of the systemic circuit, and name the areas each serves.

from the left ventricle the arteries of the systemic circuit transport oxygenated blood and nutrients to all organs and tissues, ultimately returning deoxygenated blood to right atrium. all arteries originate from the aorta, and all veins merge into the superior and inferior vena cava

identify the branches of the superior vena cava and the areas each serve.

the external jugular vein drains superficial structures of the head and neck. vertebral vein drains the cervical spinal cord and the posterior surface of the skull. internal jugular vein drains deep structures of the head and neck. brachiocephalic vein forms as the jugular veins empty into the subclavian vein, receives blood from the vertebral vein and the internal thoracic vein draining the anterior chest wall. superior vena cava carries blood from the two brachiocephalic veins to the right atrium. internal thoracic vein collects blood from the intercostal veins and delivers is to the brachiocephalic vein. axillary vein is joined by the cephalic vein on the lateral surface of the first rib forming the subclavian vein which continues into the chest. brachial vein merges with the basilic vein and becomes the axillary vein which enters the axilla. cephalic vein extends along the lateral side of the arm. median cubital vein interconnects the cephalic and basilic veins. ulnar vein and radial vein drain the deep palmar arch before crossing elbow then fuse to form the brachial vein. cephalic vein median antebrachial vein and basilic vein drain the superficial palmar arch. digital veins empty into superficial and deep veins of the hand which are connected to form the palmar venous arches.

Describe the structures of capillaries and their functions in the exchange of dissolved materials between blood and interstitial fluid.

•Continuous capillary Permits diffusion of water, small solutes, and lipid-soluble materials Prevents loss of blood cells and plasma proteins Some selective vesicular transport •Fenestrated (fenestra, window) capillary Contains "windows," or pores, penetrating endothelial lining Permits rapid exchange of water and larger solutes •Sinusoids (sinusoidal capillaries) Permit more water and solute (plasma proteins) exchange