term test 3- Cardiac, Neuro and Digestion Flashcards
where does most of the blood lie in the circulatory system?
venous system, followed by lungs or systemerric arteries, then the heart, then the capillaries.
why is the venous system contain the most blood?
it acts as a reservoir.
what are the body parts involved in the air passage way? name them in order.
nasal cavity/oral cavity>pharynx>larynx>trachea>bronchus>bronchial tress>terminal bronchioles>alveolar sac>alveolus
go into detail about the larynx
its where air is deviderted towards the lungs and food is deverted toward the stomach. it also contains the vocal cords (lining tissues of the larynx
)
go into detail about the pharynx
its a muscular passage (throat) and paired with an epiglottis.
how does air pass from one alveolus to another?
pores
describe what happens when you breath in, and out
chest expands, ribs separate the diaphragm contracts (pulls down*)
chest contracts, lungs shrink, and diaphragm relaxes (expands*)
what are the “needs” for inspiration to occur
the lungs must be able to expand when stretched- and they must have high compliance (stretch ability and dispensability)
what is lung compliance?
its the change in lung volume per change in trans pulmonary pressure. lung disease reduces compliance.
what is the formula for compliance?
dV/dP
what is the difference between expiration and elasticity?
expiration is when the lungs must get smaller when tension is released. they must have elasticity.
elasticity is the tendancy of a structure to return to its initial size after being distended.
why/ how are the lungs elastic?
content of elastin proteins, the lungs are normally stuck to the chest wall, so they are always in a state of elastic tension. it ^ during inspiration and decreases during expiration.
what is an interesting property of the lungs, that make it impossible to breath with a chest wound
ion order to inflate the lung MUST be attached to the inner wall of the chest cavity. the attachment is make with membranes called pleural membranes!
what are pleural membranes? PMs
one membrane layer attached to the surface of the lung, and one membrane layer attached to the inner wall of the chest cavity. it produces a mucous-rich layer called pleural fluid ,into the space between the pleural space (PS).
* it holds the membranes together.
how des surface tension play a role in respiration
its exerted by fluid in the alveoli.
(the fluid contains surfactant, released by type 2 alveolar cells, this fluid lowers surface tension, and stops alveoli from collapsing during expiration.)
Explain respiratory Distress syndrome.
pre-mature babies do not have sufficient surfactant and their aleveoli are collapsed. Eventually they will develop it, but will need to be on special machines until they mature enough.
where can you find anatomical dead space?
nose, mouth, larynx, trachea, bronchi, bronhciloes (no gas exchange occurs, and is about 150 ml)
what are two interesting properties of hemoglobin
it chemically combines with O2, and can also release the gas when cells need it.
hemoglobin acts as an O2 shuttle from the lungs to body tissues
what is the role of CO2 in regulating the binding of O2 with hemoglobin in the lungs?
Co2 difusses from the blood to the alveoli and blood Co2 levels are low. this reduces the acidity of blood in the lungs
what is the role of CO2 in regulating the binding of O2 with hemoglobin in the tissues?
blood CO2 levels are high because the cells produce the gas as an excretory product and O2 levels are low because it is being used by cells this increases the acidity of blood in the tissues.
what role does acidity in the plasma play?
it determines whether O2 combines with hemoglobin to form oxyhemoglobin or whether O2 is released from oxyhemoglobin.
when does blood acidity decrease?
when CO2 diffuses from the plasma to the alveolar sac allowing O2 to combine with Hb to form oxyhemoglobin
when does blood acidity increase?
when CO2 difusses from body cells to the plasma causing oxyhemoglobin to dissociate into Hb and O2; the O2 diffuses into the body cells.
explain CO2 transport in the general body tissues?
the constant production of CO2 causes the bicarbonate equation in the red blood cells
explain CO2 transport in the lungs
CO2 is being lost to the alveolar air sac,
how does total atmospheric pressure increase?
it increases by one atm for every 10m below see level.
humanswould not be able to go past 30m. but they can due to the mammalian diving reflex. name the reflexes
drop in heart rate
vasoconstriction
spleen releases RBS’s carrying O2
blood shift-plasma fills up lung BV
name some problems with diving
cardiac arrest, black outs, hyper-gas narcosis
what is special about SCUBA’s?
they are composed of mix air (nitrogen included)
must ascend slowly to avoid nitrogen bubbles to enter blood. (pain is called the bends)
whats the treatment for the bends?
hyperbaric oxygen therapy. (given O2 at 100% at 3 atm, to raise the plasma concentration.
`what is acute mountain sickness?
when higher than 5000 feet. headaches, low arterial pressure blanace with hypocapnia causes cerebral vasoconstriction. 9000 feet= pulmonary edema, 10,000 feet= cerebral edema
how do veins return blood to the heart?
the pressure is too low to return the blood, so they have extra layers of muscle (to expand). and they pass between skeletal muscle groups which provide contractions to help move blood back .
what makes blood stop from pouring back into the venous system?
venous valves.
exmplane how large arteries react to blood pressure changes?
they have layers of elastin fibers between the smooth muscles cells of the tunica media. they expand when the pressure rises, as a result of the ventricles contraction. (the retract when the blood pressure falls)
explain how small arteries react to blood pressure changes?
are less elastic and so their diameter only changes slightly.
what increases/decreases blood flow to the capillary bed?
vasoconstriction decreases blood flow, and vasodilation increases it.
describe the phenotype of capilaries
they are once endothelial cell thick,
what are the muscle layers of a large artery, medium artery, and arteriole,
large: tunica externa>tunica media>tunica interna (elastic layer>endothelium)
medium: tunica externa> tunica media> tunica interna
srteriole: prepaillary sphincter>endothelium>lumen
what are the layers of a large vein, medium vein, and a venule.
large: tunica externa> tunica media>endothelium>tunica interna>lumen.
medium: tunica externa>tunica media> tunica interna>valve
venule> tunica externa>endothelium>valve.
which side of the heart woks harder, and which side is thicker.
Lv works harder (5-7x), and has a thicker wall (almost 2-3 x)
what prevents backflow of blood?
valves.
name all 4 valves, and where they are located.
AV valve (between RA and RV): tricuspid valve
AV valve (between LA and LV) bicuspid valve
pulmonary semilunar valve (between pulmonary artery and RV)
Aortic Semilunear valve (between LV and aorta)
when do the valves open and how?
they are controlled by pressure and contractions. when the ventricles contract the valves open, and during the time venricular relaxation, the semilyar valves snap shut so blood doesnt flow back.
what is the muscle wall called between the RV and LV?
interventricular septem.
what are the strong muscles found in the RV and LV called?
papillary muscles.
describe the blood flow in a heart beat.
both atria fill with blood then contract simultanerously sending blood to ventricles. this is followed by simultaneous contractions of both ventricles (0.1-0.2 seconds later).
explain the difference between disable volume and synodic volume?
the heart can never fully empty, and you can find out how much it can hold by measuring its biggest volume (end disable volume) and subtracting its smallest volume (synodic volume).
the stroke volume is all the blood that leaves the heart after one pump.
how do you measure the cardiac out put?
its the “Heart rate x Stroke volume= CO”
what happens to stroke volume when your heart is beating faster?
it goes down.
what is an average cardiac rate?
75 bpm, and each cycle lasts 0.8 seconds.
what are the 3 regions of the hart that can spontaneously generate action potential?
- Senatorial node can function as a pacemaker.
- Av node
- purkinje fibers.
how are the AP originated at the SA node
they spread to adjacent myocutes in the RA and LA through gap junctions. however the atria and ventricles are searated so specialized cells are needed to mvoe the imulse atria to ventricles. these are specialized myocardial cells in the AV node.
explain the movement of the impulse from the SA node.
goes to AV node
continues through AV bundle
descends down the intraventricular septum, divides the right and left with purkinje fibers in the ventricle wall
spreads from endocardium to epicardium causing both ventricles to contract simultaneously.
what machine measures the potential differences generated by the heart? and what are the recordings called?
electrocardiograph, and the recording is called an electrocardiogram (ECG). the results are from the production and conduction of AP in the heart.
what are heart muscle cells called?
myocardial cells. they contain actin filaments and myosin filaments arranged int he form of sarcomeres.
how do myocytes connect, and what is that important?
they conenct via gap juncitons at the ends of each myocardial cell, which permits electrical impulses to be conducted cell to cell. these gap junctions stain as intercalated discs.
how does an electrical signal cause a heart muscle to contract?
cardiac AP originate in the SA node, contraction follows Ca2+ induced Ca2+ releas: Ca2+ enters myocytes cytoplasm through voltage gated channels in cell membrante, these stimylate opening of Ca2+ release channels in the sarcoplasmic reticulum SR. So Ca2+ from the voltage channels serves as messenger for Ca2+ release channels.
for the heart muscle to relax, Ca2+ in cytoplasm must be pumped back into the SR>
describe excitation-contraction coupling in cardiac muscle in 5 simple steps. (starting with voltage gated calcium channels opening)
- Ca2+ diffuses from ECF to cytoplasm
- Ca2+ release channels on SR open.
- Ca2+ released form SR binds to sarcomere stimulates contraction
- Ca2+ ATPase pumps calcium bac into SR
- Myocardial cells relaxes.
describe the microanatomy of muscle cells
cells are arranged into long, rod-shaped organelles that are called myofibrils.
the myofibril rods have a distinct straited pattern of alternating light and dark bands.
what are z-discs?
they are proteins that act as anchors for thin protein filaments; these consist of a protein called actin, and other proteins
what are sarcomeres?
they are section of the fibre between Z-discs.
what is happens when muscles contract?
the thin filaments slide past one another, and the Z-discs move closer together. the overlapping of the thin and thick filaments gives the striated patter. they contractions are caused by the swiveling of the head on the thick filaments.
what are thick filaments?
they are made up of rod-shaped proteins, that have an angular head at one end.
what are the major molecues that play in muscle contraction?
actin, myosin
tropomysosin (attached to actin)
and troponin complex (3 subunits attached to tropomyosin).
explain the contraction process
myosin head has an actin bindin site (BS) and an ATP-BS. when ATP is hydrolyzed to ADP, myosin head is activated and changes orientation.
attachment of Ca2+ to troponin causes movemen of the troponin-tropomyosin complex, exposing BS on actin. Myosin cross bridges attach to actin and undergo a power stroke.
what are the differences between cardiac and skeletal muscle contractions?
skeletal requires external stimulation by somatic motor nerves, they are long and fibrous, and they have direct excitation contraction coupling between the transverse tubules and SR
cardia produces AP automatically form the SA node, they are short, branched and interconnected (gap juncitons), and here the Ca2+ channels inthe plasma membrane, and the Ca2+ release channels in the AR do not directly interact, instead its induces, and released.
what 3 resistance factors effect blood flow?
- tube/blood vessel length
- viscosity of the blood
- tube/blood vessel radius
whats the number 1 leading cause of death?
cardiac vascular disease with coronary heart disease as number 1.
What is coronary artery disease CAD
when you have plaque build-up in or or more of the 3 coronary arteries. if it obstructs blood flow it causes pain. it if interrupts blood flow it cases a myocardial infraction (heart attack)
what is a congestive heart?
is when the heart walls are not portioned correctly (lack or too much muscle). leads to insufficient flow, and can cause water retention or edema because of the back-up of blood in the heart.
how can you treat congestive?
b-blockers: they target beta receptor, (hear mostly b1-adrenergic receptors) the b-receptors bind catecholamines, thus b-clockers are blocking binding and reducing heart rate. this also acts on the RAAS system of the kidneys, and dilates the arteries.
What ia an Aneurysm?
caused by weakling of the vessel walls, and causes the artery to bulge.
what is anatomy, and what is the anatomy of the nervous sytem?
anatomy= nervous system structure. it breaks down into two divisions:
Central nervous system (brain and spinal cord)
Peripheral nervous system (nerves and ganglia)
what is physiology, and what are the 3 functions of the nervous system?
its the function fo the nervous system.
- control of movement and some functions (motor nerves)
- detection of external stimuli (sensory nerves)
- integration of neuronal activity and connections: (association neuron).
what are the two things neurons really do?
- conduct electrical signals (AP)
2. Release “chemical” signals (neurotransmitters)