Circulatory and Respiratory systems Flashcards
(34 cards)
1
Q
Overview on how the vardiovascular system works
A
- composed of muscular, four chamered heart and a network of blood vessels and blood itself
- blood pumped into aorta, branches into a series of arteries, into artierioles and then into capillaries
- exchange of gases, nutrients and cellular waste ovvurs via diffusion across capillary walls
- capillaries converge into venules then veins to bring deoxygenated blood back towards the heart
- from heart goes to lungs wehre CO2 is exchanged for O2 and returns to heart
2
Q
anatomy of the heart
A
- right side pumps deoxygenated blood into pulmonary circulation (twds lungs)
- left side pumps oxygenated blood into systemic circulation (though body)
- two upper chambers = atria which is thin walled
- two lower = ventircles,muscular bc responsible for generate force that propels systemic circulation & pumps at higher resistance
*over time left ventricle can become hypertrophied (enlarged) leading to congestive heart failure and other cardiovasuclar disease
3
Q
explain blood flow through the heart
A
- blood returning form body to heart goes into right atria, triscupid valve, reight ventricle, pulmonary semi-lunar valve, pulonary arties, lungs
- pulmonary veins, left atrium, mitral valve, left ventricle, out aortic semi lunar valve into systemic circulation
4
Q
What are the different valves in the heart and their roles
A
- atrioventricular valves are lcoated between the atria and ventircles on both sides of the heart, prevent backflow into atria
- tricuspid valve: on right side of heart and has 3 cusps
- mitral valve: on left side with 2 cusps
- semilunar valves: have 3 cusps and are located between the left ventricle and the aorta, and between the right ventricle and pulmonary artery (pulmonary valve)
*the lub-dub sound of heart beat is made up of the closing of the atriobentricular and semilunar valves respectively
5
Q
explain contraction
A
- cycle composed of systole and diastole which makes up the heartbeat
systole: ventircles contract forcing blood out heart into lungs and circulatory system
diastole: period of cardiac muscle relaxation during which blood drains into 4 chambers
6
Q
what are the 2 numbers of blood pressure
A
- systolic blood pressure measures the pressure in patients blood vessels when ventirclces are conracting
- diastolic if the pressure durign relaxation
7
Q
what is cardiac output
A
- total volume of blood the left ventricle pumps out per limute
CO = stoke volume (volume of blod pumped out of ventricle per contraction) x Hear rate (beats/min)
8
Q
how is Heart Rate controlled
A
- cardiac muscle conracts rhythmically without stimulation from the nervous sytem -> impulses spread thorugh internal conducting system
- an ordinary cardiac contraction originates in and is reg by sinoatria node (SA node, pacemaker)
- impulse arrives at the atrioventricular (AV) node which slowly conducts impulses to rest of the heart, allowing for enough time for atrial contraction and ventricels to fill with blood
- impulse then carries out by bundle of His (AV bundle) branching into right and left bundle branches
- finally to purkinje fibers in walls of both ventricles generating a strong contraction to force blood out
9
Q
what is the SA node
A
- sinoatrial node, pacemaker
- specialized tissue located in wall of the right atrium
- speads impulses throguh both atria, stimulating them to contract simulanteously
10
Q
what system modifes the rate of contraction
A
- autonomic nervous sytem
- parasympathetic NS innervates the heart via vagus nerve to cause a decrease in the HR
- sympathetic NS innervates the heart viavervical and upper thoracic ganglia and causes an inc in HR
- adrenal medulla exerts hormonal control vai epinephrine secretion to cause an inc in HR
11
Q
what are the different types of blood vessels
A
Arteries
- thick walled, muscular, elastic vessels that transport oxygenated blood away form heart
- EXCEPT pulmonary artery which transports DEoxygenated blood from heart to lungs
Veins
- relatively thin walled, inelastic vessels that conduct deoxygenated blood towards the heart
- EXCEPT pulmonary vein which transports OXYgenated blood from lungs to heart
- much of blood flow in veins depends on compression by skeletal muscle during movement
- larger veins require vales to prevent backflow bc gravity
Capillaries
- very thin walls composed of single layer of epithelial cells
- gases, nutrients, enzymes, hormones, and wastes are readility diffused across
- smallest diameter, RBC often must travel through them single file
12
Q
role of lymph vessels
A
- lymphatic system is a secondary circulatory system distinct from cardiovascular circulation
- vessels transport excess interstitial fluid (lymph) to cardiovasualr system keeping fluid levels in the bdoy constant
- smallest lymphatic vessels = lacteals, collects fats in the form of chylomicrons from the villi in the small intestine and deliver them into the blood stream bypassing the lier
- lymph nodes are swellings along lymph vessels containing phagocytic cells (lymphocytes) that filter lymph to remove and destroy foreign partilces and pathogens
13
Q
what is in blood
A
- human body o average contains 4-6L of blood
55% liquid (plasma) and 45% cellular components
- plasma is composed of nutrients, salts, respiratory gases, wastes, hormones and blood proteins (immunoglobulins, albumin, fibroingogen)
- cellular components = erythocytes, leukocytes and platelets
14
Q
what are leukocytes
A
WBC
- larger than erythrocytes and serve as protective functions
15
Q
what are platelets
A
- cell fragments that lack nuclei and are involved in clot formation
- many drugs inhibit platelet formation or adhesion to decrease clot development
16
Q
what are Erythrocytes
A
RBC: oxygen carrying components of blood
- contains up to 250 mol of hemoglobin which can each bind 4 mol of O2
- once bound to O2 its called oxyhemoglobin and is the primary form of oxygen transport in the blood
- distinct bioconcave shape gives increased SA for gas exchange and greater flexibilty in capilaries
17
Q
how are erythrocytes formed
A
- stem cells in bone marrow, formation is stimulated by erythropoietin (hormone made in kidneys)
- in bone marroe erythrocytes lose their nuclei, mitochondira and membranous organelles
- once mature they circulate in blood for 120 days and then are phagocytized by special cells in spleen and liver
- finding immature erythrocytes circulating in the blood stream before they have lost organelles can be an indicator of various diseases (hemo lytic anemia which caused by rapid destruction of RBCdue to infection or disorder)
18
Q
what do erythrocytes display on cell surface
A
- antigens, two major groups are ABO nd Rh factor
19
Q
A
20
Q
why is it important that blood types be matched during transfusion
A
- if not matched RBC will be clumped (rejected) by antibodies in the plasma
- AB blood is the universal recipient bc does not have anti-A or anti-B antibodies
- type O is universal donor bc doe snot have surface antigens but has anti-A and anti-B
21
Q
what is the Rh factor?
A
- another antigen that may be present on surface of RBC
- can be Rh+ or Rh-
*particulary important during pregnancy bc if mother is Rh- and fetal RBC are Rh+ and enter maternal circulation or vice versa
- can result in serve anemia for the fetus known as erythroblastosis fetalis
note: anti-A and anti-B antigens cannot cross the placenta
*this is also to be considered in blood transfusions
22
Q
how does the transport of gases occur?
A
- erythrocytes transport O2 throughout the circulatory system
- hemoglobin mol in erythrocytes bind to O2 bc contain iron
- when bound to CO2 called deoxyhemoglobin
23
Q
explain the transport of nutrients and waste
A
- amino acids and simple sugars are abs in blood stream @ interstitial capillaries, after processing are transported throughout the body
- metabolic waste products (water, urea, CO2) diffuse into capillaries form surrounding cels to be delivered to excretory organs
24
Q
explain clotting
A
- when platelets come into contact w/ exposed collagen of a damaged vessel they release a chemical to nieghbouring platelts to adhere to one another forming the platelet plug
- both platelets and damage tissue release clotthing factor thromboplastin which with the aid of cofactors Ca and vit Kconverts inactive plasma protein into prothrombin then into active thrombin
- thrombin converts fibrinogen (also plasma prot) into fibrin
- threads of fibrin coat the damaged area and trap blood cells forming a clot which prevents excessive blood loss while the damaged vessel heals itself
- fluid left after clotting =serum
*process called clotting cascade
25
what does warfarin do
- drug working as an anticoagulant
- inhibits the recycling of vitamin K inhibiting clotting
26
pathway of air into lungs
- air passes through nose, pharynx (throat), larynx, trachea, bronchi, bronchioles and alveoli
27
where does gas exchange occur
- very thin walls of alveoli and pulmonary capillaries
- alveoli = air filled sacs at the terminals of airway branches
3 hundred million prvide 100m2 of moist respiratory surface for gas excahnge
- pulmonary capillaries surround the alveoli, gas mvoes from region of higher partial presure to regions of lower partial pressure
- oxygen diffuses from alveolar air into blood while CO2 diffuses from blood into lungs and exhaled
28
what is the function of the respiratory system
- provide the necessary energy for all body function
- provides large surface area for gas exchange and continuously moving oxygenated air over this area protecting the respiratory surface from infection dehydration and temp changes
- also assists in regualtion of body pH by regualting rate of CO2 removal from blood
29
what occurs during inhalation
- diaphragm contracts and flattens
- external intercostal msucles contract prushing the rib cage and chest wall up and out
- phrenic nerve innervates the diaphram and causes it to contract and flatten
- these cations cause the thoracic cavity to inc in volume
- the volume increase reduced the pressure causing the lungs to expand and fill with air resulting in inhalation
30
explain exhalation
- passive process
- lungs and chest wall are highly elastic and tend to recoil to original positions after inhalation
- diaphragm and external intercostal muscles relax and chest wall pushes inward
- the dec in thoracic cavity volume causes the pressure to inc forcing air out alveoli and lungs to deflate
31
what is surfactant
- protein complex excreted by cells in the lungs
- keeps lungs from collapsing, dec surface tension and assists with luing function
- babies bron prematurely do not always produce sufficeint surfactant so must be given artificial surfactants until can produce it on their own
32
how is ventilation regulated
- regulated by neurons in the medulla oblongata
- rhythmic discharges stimulate the intercostal muscles or diaphragm to contract
- when partial pressure of Co2 rises the medulla oblongata stimulated an inc in the rate of ventilation
33
how is the proper conc of Oxygen, carbon dioxide and hydrogen ions maintained
- excessive CO2 and H+ ion levels are the primary stimuli for respiration
- when CO2 and H+ levels are increased the respiratory center stim both inspiratory and expiratory muscles of the lungs
- oxygen blood levels do not have a significant effect on the respiratory center
- oxygen blood levels are monitored by peripheral **chemoreceptors** which indirectly stimulate the respiratory center
- cahnges in acid-base chemistry due to kidney function can also influence ventilation
34
explain lung capacity
- **total lung capacity** represents the maximum volume of air lungs can hold
- at rest humans only breathe as much as needed: move sig smaller volumes of air then total lung capacity called **tital volume**
- under stress sig more air can be moved then tital volume, this called **vital capacity**
- the **inspiratory reserve volume** is the diff between vial capacity and upper and lower limit of tidal reserve volume
- even w/ heavy breathing lungs wil never empty since a **residual volume** will always remain (diff ebtween vital vapacity and total lung capacity)
- if residual volume was removed lung may not be able to re-infalte due to internal surface tension
