A&p 2 Exam 2

the physiology of blood flow in the cardiovascular system

the presence of a higher pressure in one area than in another area

higherst in the left ventricle and lowest in the right ventricle

the outward force that blood exerts on the walls of the blood vessels

the volume of blood that flows per minute and is determined by blood pressure and resistance

directly proportional; as pressure gradient increases so does blood flow

resistance, cardiac output, and blood volume

the majority of resistance to blood flow takes place away from the heart in the periphery where the arteries brance and become smaller

vessel size, viscosity and vessel length

refers to how thick blood is; as viscosity of a liquid increases, peripheral resisistance also increases

blood pressure will increase

blood vessels become fuller and blood pressure increases

the amount of water in the blood

pressure in the arteries during systole

120 mmHg

pressure in arteries during diastole

80 mmHg

the difference between the systolic pressure and the diastolic pressure

a sphygmomanometer and a stethoscope

one way valves, skeletal muscle pump, respiratory movements

function to keep blood from blowing backwards in the veins

when skeletal muscles contract they squeeze on the veins and propel the blood toward the heart

they help in the thoracic and abdominopelvic cavities

the sympathetic nervous system releases the neurotransmitters norepinephrine and epinephrine in response to stressors in the body (does not have to be major stressors)

-these neurotransmitters cause an increase in heart rate and contractility which increases cardiac output and thus increases blood pressure

opposite of the sympathetic nervous system

-releases neurotransmitter aceytylcholine which causes heart rate to slow which decreases cardiac output thus loweering blood pressure

stretch receptors in the aorta and carotid arteries

detect the presence or absence of certain chemicals

chemoreceptors that regulate blood pressure and are located in the aortic arch and in the carotid artery close to the baroreceptors

epinephrine, norepinephrine and thyroid hormone

acts in indirect manner to increase cardiac output

epi and norepinepherine cause vasoconstriction in many blood vessels in the body and thus increase resistance and blood pressure

-angiotensin-II is a very powerful vasoconstrictor and will sharply increase peripheral resistance causing an increase in blood pressure

antidiuretic hormone, aldosterone, atrial naturetic peptide (ANP)

secreted by the posterior pituitary gland and acts in the kidney causing an increase in water reabsorption and decrease in urine production

released by the adrenal cortex and acts in the kidney causing an increase in the retention of sodium by the kidney; since water goes where sodium goes there is increase in total body water and thus an increase in blood volume

causes the kidneys to invrease the elimination of sodium and water which decreases blood volume

"high blood pressure"

systolic pressure is between 140-159 mmHg and diastolic is 90-99

systolic is greater or equal to 160 mm Hg and diastolic greater or equal to 100mmHg

increased risk or coronary artery disease, stroke, heart failure, kidney disease, vascular disease and more

lifestyle modificaitons, dietary modifications like low salt and decrease cholesterol intake and drug therapy that is aimed at one or more of the three factors controlling blood pressure

abnormally low blood pressure; systolic less than 90mm and diastolic less than 60mmhg

reduced blood volume: from dehydration, vomiting, diarrhea, overuse of diuretics

decreased cardiac output: caused by medications that lower heart rate or a decreased stroke volume caused by heart failure

vasodilation: septic shock resulting from a severe bacterial infection can cause vasodilation

blood flow through a capillary bed to a tissue and takes into account the mass of the tissue

taking blood flow and dividing it by the mass in grams of tissue

capillaries have extremely thin walls which allows them to function as exchange vessels for nutrients, gases, ions, water, hormones and waste between blood and the tissues.

diffusion and osmosis

diffusion through the endothelial membrane

transcytosis

small openings between the endothelial cells

small substances such as monosaccharides and amino acids

lipid soluble substances such as exygen, carbon dioxide and ertain lipids can generally enter and exit the capillary by diffusing through the endothelial cells; diffusion always takes place down the concentration gradient

transcytosis is a process in which the molecules are taken into the cell by endocytosis and then moved out the other side by exocytosis

continuous capillaries; fenestrated capillaries; sinusoidal capillaries

the least "leaky" and permit the fewest substances to enter or exit the blood. their endothelial cells are joined by tight junctions

contain fenestrations or openings in the enothelial cells whcih makes them more leaky than continuous capillaries

have discontinuouis sheets of enothelium and very large pores in the enothelial cells; leakiest of all capillaries

ensures that the correct amount of blood is delivered to match the tissue's activity level

myogenic mechanism and metabolic controls

relies on properties inherent in the smooth muscle of the arteriole vessel supplying the capillary beds; increases in blood pressure in the arterioles activates stretch sensors which result in vasoconstriciton. the reverse is true if there is a decrease in blood pressure

cellular metabolism generates chemicals that can act to regulate tissue perfusion

because of the contraction forces in the ventricular muscle, blood only flows through the coronary circulation during diastole; the main regulatory mechanism of the coronay circulation is the metabolic control

the brain is more intolerant of ischemia than any other tissue in the body; a loss of conciousness will occur within secons of a sudden decrease in perfusion pressure

autoregulatory mechanisms including myogenic and metabolic controls

when exercise begins metabolic conditions in the skeletal mescle cause casodilation resulting in an increase in blood flow to the muscle

temperature: warm conditions will cause vasodilation while cold conditions will cause vasoconstriction

by passing through small pores and fenestrations as well as moving via osmosis and filtration

the movement of a fluid driven by a force such as pressure or gravity

the force that a fluid exerts on the wall of its container

filtration

movement of water from low solute concentration to area of high solute concentration

the solute particles in a solution exert a pulling force on water

the difference in osmotic pressure between the capillary and the interstitial space

excessice water in the intersitial fluid

an increase in capillary hydrostatic pressue and a decrease in the oncotic pressure (caused by liver failure as a result of chronic alcoholism, viral infection, or cancer)