Circulatory and Respiratory systems Flashcards
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
19
Q
A
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
27
Q
where does gas exchange occur
A
- 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
30
Q
explain exhalation
A
- 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
34
Q
explain lung capacity
A
- 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
