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a&p II test 3
Question | Answer |
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what is the structure of arteries? | have a tunica intima, tunica media, and tunica aventitia. because they are exposed to highest pressure of any vessels they have thickest tunica media contain elastin to stretch and recoil and smooth muscle to dilate and constrict |
what is the structure of veins? | have tunica intima, tunica media, and tunica adventitia, experience least pressure. have thinner walls than arteries, larger lummens which allows themk to accomodate lrg volume of blood, tunica adventitia is largest layer |
what is the structure of arteriols | smallest arteries, tunica media is almost entirely smooth muscle to allow them to constrict and relax, vasomotor fibers regulate activity of smooth muscle |
why is vasomotor regulation important in arteriols? | because small changes in blood vessel diameter greatly influence blood pressure and blood flow |
what is the structure of venules? | formed when capillaries unite, lrg vennules have spares tunica media and thin tunica adventitia, small venules drain into capillaries and consist of endothemlium around which a few fibroblast congregate. |
what is the structure of capillaries? | smallest vessels, link between arteries and veins in the pathway of blood, consist of just thin tunica intima, role is to exchange materials between blood and interstitual fluid |
what are the types of arteries? | elastic arteries, muscular arteries, and arteriols. |
elastic arteries | aka conucting arteries, large vessles like aorta and pulmonary trunk, tunica media has many elastic fibers and few muscle cells which allows them to expand and recoil to propel blood onward , elasticity evens out pulse force |
muscular arteries | aka distribution arteries, medium sized, tunica media has many muscle cells and little elastin enabling them to activily constrict and relax, deliver blood to specific body organs, |
what are the types of veins? | large veins, medium veins, and venules |
large veins | have all three tunica layers, thick tunica adventitia, thin tunica media, contain venous valves which are folds of tunica intima to control backflow of blood |
medium veins | thin tunica media and few muscle cells, tunica adventitia has longitudinal bundles of elastic fibers |
what are the types of capillaries? | continous capillaries, fenestrated capillaries, sinusoidal capillaries, |
continous capillaries | have complete endothelial linning, are found in all tissues except for epithelia and cartilage, they permit the diffusion of water, small solutes, and lipid soluable materials, block blood cells and plasma protiens |
fenestrated capillaries | have pores in edothelial linning, premit rapid exchange of water and larger solutes between plasma and interstitial fluid, found in choroid plexus, endocrine organs, kidneys, intestinal tract |
sinusoidial capillaries | have gaps between adjacent endothelial cells; liver, slpeen, bone marrow, endocrine organs, permit free exchange of water and large plasma protiens between blood and interstitial fluid, phagocytic cells monitor blood at sinusoids |
vasoconstriction | the contraction of arterial smooth muscle by the ANS |
vasodilation | relaxation of arterial smooth muscle, enlarging the lumen |
venoconstriction | systemic veins constrict |
how does the composition of capillary walls differ from other vessels | capillary walls are made of just a tunica intima and allow excange of nutrients through the wall were as other vessles do not and are composed of all three layers |
location and function of venus reserve | the maount of blood that can be shifted from veins in the liver, skin, and lungs to the general circulation |
anastomoses | direct connections between arteriols & venules. when dilated blood bypasses capillary bed & flows to venous circulation, pattern of blood flow is regulated primarily by smympthetic innervation under control of cardiovascular centers of medulla oblongata |
pulmonary circuit | deoxygenated blood arrives at heart from systemic circuit, passes through right atrium and right ventricle, enters pulmonary trunk, at lungs carbon dioxide is removed and oxygen added, oxygenated blood returns to heart and is distributed |
what vessels carries oxygen rich blood in pulmonary circuit? | pulmonary veins |
what vessels carry deoxygenated blood in pulmonary cicuit | pulmonary arteries |
systemic circuit | supplies all body except for pulmonary circuit, blood moves from left ventricle to ascending aorta branches of aortic arch deliver to head, neck, and shoulders. descending aorta delivers blood to thoraci, abdoinal, and arteries of pelvis and lower limbs |
subclavian arteries | leaving the thoracic cavity; become axillary artery and brchial artery |
brachial artery | divides into radial artery and ulnar artery which supply fingers |
common carotid arteries | divid into external carotid artery which supplies neck jaw and face and internal carotid artery which supplies brain |
vertebral arteries | supply brain with blood |
thoracic aorta | supplies organs of the chest |
abdominal aorta | supplies body wall, kidneys, urinary bladder |
superior vena cava | recieves blood from tissues of head neck cheast shoulder and upperlimbs...deoxygenated |
inferior vena cava | collects blood from tissues inferior to diaphram...deoxygenated |
hepatic portal system | connects two capillary beds, delivers nutrient laden blood from capillaries of digestive organs to liver sinusoids for processing |
hepatic portal veins | inferior mesentric drains large intestine, splenic veins drains spleen part of stomache and pancreas, superior mesentric drain stomach, sm intestine, part of lrg intestine, gastric veins drian stomach, cystic drains gallbladder |
what is the role of the placenta and umbilical cord before birth? | blood flows from the illiac arteries of the fetus to the placenta were it is oxygenated then the umbilical cord dilivers the oxygenated blood to the heart via the umbilical vein which then circulates through the body to the umbilical arteries |
ductus arteriousus | short vessel that connects the pulmonary and aortic trunks while baby is in the placent then after birth the babay breaths and the ductus anteriousus constricts |
foramen ovale | interarterial opening covered by valve like flap that directs blood from left to right atrium while baby is in placent but during birth after the baby breaths rising left atrial pressure closes it |
ductus venosus | a vascular connection of veins within the developing liver that the umbilical vein drains into. after birth when the placenta connection is broken the vesels degenerate |
blood flow | blood flow is directly proportional to the pressure (increase in pressure, increase in blood flow) and inversly proportional to the resistance (increase in resistance, decrease in flow) |
blood pressure | aterial pressure usually reported in mm HG. average systemic arterial pressures range from an avg of 100 mm HG at the entrace to the aorta to roughly 135 mm Hg at the start of the capillary network |
total peripheral resistance | the resistance of the toatl cardiovascular system |
pulse pressure | pp= systolic pressure ( 120 mm HG) - diastolic pressure ( 80 mm Hg) pp= 40 mm Hg |
mean arterial pressure | MAP= diastolic pressure + 1/3 pulse pressure MAP= 80 + (1/3)40 MAP = 80 + 13.3 MAP= 93 |
diffusion through membranes of capillaries | lipi soluble molecules like oxygen and carbon dioxide diffuse through the lipid phase of the plasma membranes. they are able to move across the membrane from areas of higher concentration to areas of lower concentration w/o help from trasnport proteins |
transport by vessicles of capillaries | non lipid soluble molecules are translocated across the membrane by endocytosis and exocytosis. |
filtration | driven by hydrostatic pressure, water and small solutes are forced through capillary wall which leaves larger solutes in the blood stream |
reabsorption | the result of osmotic pressure. |
bloos colloid osmotic pressure | equals pressure required to prevent osmosis and is caused by suspeneded blood proteins that are too large to cross capillary walls |
how does the musculatory pump aid venous return? | the contraction of skeletal muscles near a vein compress it helping to push blood toward the heart. valves within veins ensure that blood flows in one direction. cycles of contraction and relaxation that accompany your normal movements aid return |
how does the repiratory pump aid venous return | when you inhale your thoracic cavity expands causeing a drop in pressure which pulls blood into the inferior vena cava and right atrium from sm veins of abdominal cavity, as you exhale thoracic cavity decreases and blood is forced into right atrium |
explain how autoregulation controls blood flow to tissues | as long as blood pressure is normal tissues can regulate when they need blood asnd when they dont. when tissues get low on oxygen they need blood but when they are full of oxygen they wont need blood again until they get low |
explain the role of the precapillary sphincter in autoregulation | a cuff of smooth muscle fibers that surround the root of each true capillary acting as a valve to regulate the blood flow into the tru capillaries |
what are some chemicels that cause vasodilation and when does it occur? | occures when decreased oxygen are increased carbond dioxide, happens when latic acid is released, nitric oxide is released, rising k or hydrogen ions, when chemicals for local inflammation are released, and elevated temp |
what are some of the chemicals that cause vasoconstriction and when does it occur? | happens when tissues are damaged, examples are: prostaglandins and thromboxanes |
barorecptor reflex | when blood pressure sises CV center decreases cardiac output which causes peripheral vasodilation and when blood pressure falls Cv centers increase cardiac output and cause peripheral vasoconstriction |
chemoreceptor reflex | happens when carbon dioxide levels elevate or a decrease in pH or oxygen. when stimulated the respiratory rate increases, increase cardiac output and blood pressure, vasoconstriction, and homeostasis is restored |
how does the cardiovascular system responds to maintain homeostasis? | baroreceptor reflex, chemoreceptor reflex, antidiuretic hormone, angiotensin II, erythroprotien, and natriuretic peptides |
antiduretic hormone | released by posterior lobe of pituitary, elevates blood pressure, reduces water loss at kidneys. responds to low blood volume, high plasma osmotic concetration, and circulating angiotensin II |
angiotensin II | responds to fall in renal blood pressure, stimulants: aldosterone production, ADH production, thirst, and cardiac output |
erythroprotien | release at kidneys, responds to low blood pressure, low oxygen. stimulates RBC production |
natriuretic peptides | produced by cells in right atrium or ventricular muscle cells, respond to excessive diastolic stretching, low blood volume and low BP, reducese stress on heart |
what are pathogens and the most common types? | miscroscopic organisms that cause disease. viruses, bacteria, fungi, and parasites. each attacks in a specific way |
function of the lymphatic system | protects us from disease, it produces maintains, and distributes lymphocytes |
what does lymphatic stem cells respon to? | enviromental pathogens, toxins, and abnormal body cells like cancer |
what are lymphocytes? | part of the immune response, they identify, attack, and develop immunity to a specific pathogen, are distributed by wandering through tissues, enter blood vesels or lymphatics for transport, can survive ,many years |
where are lymphocytes produced? | in lymphoid tissues, lymphoid organs, and red bone marrow. |
what is immunity? | the ability to resist infection and disease, all body cells and tissues are involved in production of immunity not just the lymphatic system |
what is lymph? | aq fluid similar to plasma but does not have plasma proteins |
lymphatic vessels | carry lymph from peripheral tissues to the venous system |
lymphoid tissues and lymphoid organs | lymphocytes, phagocytes, and other immune cells |
lymphocyte circulation | from blood to interstitial fluid through capillaries, return to venous system through lymphatic vessels, from blood plasma to lumph, back to the venous system |
major lymph-collecting vessels | the base of the thoracic duct expands into the cisterna chyli which recieves lymph from right and left lumbar trunks and intestinal fluid |
types of lymphocyte | T cells, B cells, and NK cells |
t cells | thymus dependent cells, make up 80% of circulating lymphocytes. has four main types |
four main types of T cells | cytotoxic T cells, memory T cells, helper T cells, and supressor T cells. |
cytotoxic T cells | produces cell mediated immunity, attack cells infected by viruses, associated with MHC I |
how does cytotoxic cells destroy a target cell? | release preforin to destroy antigenic plasma membrane, secrete poisonous lymphotoxin to destroy target cell, and activate genes in target cell that causes the cell to die |
memory T cells | formed in response to foreign substance, remain in body to give "immunity", immediatly form cytotoxic T cells if same antigen appears again |
helper T cells | stimulate function of T cells and B cells, remain in reserve, associated with MCH II |
supressor T cells | inhibit function of T cells and B cells, secrete supression factors, act after initial immune response, limit immune reaction to single stimulus |
B cells | bone marrow-derived, make up 10-15% of circulating lymphocytes, change into plasma cells which produce and secrete antibodies. responsible for antibody-mediated immunity |
NK cells | natural killer cells make up 5-10% of circulating lymphocytes, responsible for immunological servalliance, attack foreign cells, virus infected cells, and cancer cells |
lymphopoiesis | production of lymphocytes which involves bone marrow, thymus, and peripheral lymphoid tissues |
lymphoid organs | lymph nodes, thymus, and spleen |
lymph nodes | a filter: purifies lymph before return to venous circulation, ramoves 99% of antigens, debris, and pathogens, seell in response to inflammation |
thymus | located in the mediastium, after puberty it shrinks and that is the cause of depletion of elderly immune response |
spleen | removal of abnormal blood cells and other blood components by phagocytosis, storage of iron recycled from RBC, initiation of immune response by B cells and T cells in response to antigens |
antigens | targets tht identify any pathogen or foreign compound, |
three main types of antigens and lymph tissue | dendritic cells, macrophages, and B cells |
innate (nonspecific) defenses | always work the same way against any type of invading agent |
adaptive (specific) defenses | protect against specific pathogens, depend on activities of the lymphocytes |
physical barriers | outer layer of skin, hair, epithelial layers of internal passage ways, secretions that flush away materials, slight acidity of skin helps immune system |
immunological survelliance | is carried out by NK cells, identify and attach to abnormal cells, golgi apparatus in NK cell forms perforin, vesicles release perforins, perforins lyse abnormal plasma membrane |
inflammation | slso called inflammatory response, it is a localized response, triggered by any stimulus that kills cells or injures tissue |
three effects of inflammation | temporary repair and barrier against pathogens, retards spreas of pathogens into surrounding areas, mobilization of local and systemic defenses |
products of inflammation | necrosis, pus, and abscess |
necrosis | local tissue destruction in area of injury |
pus | mixture of debrise and necrotic tissue |
abscess | pus accumulated in an enclosed space |
fever | a maintained body temperature over 37c or 99f |
forms of immunity | innate, adaptive, active, or passive |
innate immunity | present at birth and is genetically determined, |
adaptive immunity | develops after birth |
active immunity | antibodies develop after exposure to antigen, body makes its own antigens, can be naturally acquired through enviromental exposure to pathogens or artificially induced through vaccines containing pathogens |
passive immunity | antibodies are transfered from another source (mothers milk), can be naturally acquired from mother or can be artificially induced by injection of antibodies |
MHC proteins | the membrane glycoprotiens that bind to antigens, genetically coded in chromosome 6, the major histocompatibility complex (MHC), differs among individuals |
two classes of MHC | class I, and classII |
class I MHC | found in membranes of all nucleated cells |
class II MHC | found in membranes of antigen-presenting cells, found in lymphocytes |
antibody structure | two parallel pairs of polypetide chains, one pair of heavy chains and on pair of light chains, each chain contains constant segments and variable segments. |
five types of antibodies (heavy chain) | IgG, IgE, IgD, IgM, IgA |
IgG | largest and most divverse class of antibodies, 80% of all antibodies, responsible for resistance against viruses, bacteria, and bacterial toxins, provides passive immunity to fetus, |
IgE | attaches ass an individual molecule to the exposed surfaces of basophils and mast cells,important in allergic response |
what happens when an antigen is bound by IgE molecules? | he cell is stimulated to release histamine and other chemicals that accelerate inflammation in the immediate area. |
IgD | an individual molecule on the sufaces of B cells where it can bind antigens in the extracellular fluid, binding can play a role in the senstitization of the B cell involved |
IgM | the first class of antibody secreted after an antigen is encountered, IgM concentration declines as IgG production accelerates, anti-A and anti-B antibodies in blood are IgM antibodies, they may also attack bacteria that are insensitive to IgG |
IgA | found primarily in glandular secretions such as mucus, tears, saliva, and semen. attack pathogens before they gain access to internal tissues. circulate in blood as individual molecules or in pairs |
how do IgA antibodies work? | epithelial cells absorb them from blood and attach a secretory piece, which confers solubility, before secrety IgA molecules onto the epithelial tissue |
when can a fetus produce an immune response? | after exposure to antigen, at about three to four months. |
immune system before birth | maternal IgG antibodies pass through placenta and provide passive immunity for fetus |
immune system after birth | mothers milk provides IgA antibodies while passive ammunity is lost. |
immediate hypersensitivity | a rapid and severe response to the presenve of an antigen, most commonly recognized type of allergy, includes enviromental allergies |
what are alergies? | inappropriate or excessive immune responses to antigens |
anaphylaxis | can be fatal, affects cells through out the body, changes capillary permeability, produces swelling on skin, smooth muscles of respiratory system contract which makes breathing difficult, peripheral vasodilation can cause circulatory collapse |