Applied Anatomy and Physiology Flashcards
All topics from Anatomy & Physiology
Health
A state of complete physical, mental and social well-being & not merely the absence of disease/infirmity
Fitness
Ability to meet/cope with the demands of the environment
Structure of heart
Atrium - smaller
ventricles - thicker
muscular walls
septum
left side bigger - pump to body
Arteries and veins
Vena cava - deoxy blood to right atrium
pulmonary vein - oxy blood to left atrium
pulmonary artery - leaves right ventricle with deoxy blood
aorta - leaves left ventricle with oxy blood
Valves
tricuspid - right atrium & right ventricle
bicuspid - left atrium & left ventricle
semi-lunar - right ventricle & pulmonary artery/ left ventricle & aorta
Why are valves important
Regulate blood flow & prevents backflow
Myogenic
heart initiates/stimulates its own contraction
cardiac conduction system
1.electrical impulse to SAN
2.impulse spreads through atria walls,contract,blood to ventricles
3.impulse passes through AVN which delay transmission of impulse to enable atria to fully contract
4.impulse passes through specialised fibres-bundle of his-located in septum
5.both spreads into 2 smaller bundles-purkinje fibres-spread through ventricles contract
Sympathetic nervous system
Stimualtes heart to beat faster
Parasympathetic nervous system
Returns heart to resting level
Central nervous system
Brain & spinal cord
Peripheral nervous system
Nerve cells that transmit info to & from CNS
Cardiac control system
in medulla oblongata
Chemoreceptors
Sense chemical changes in blood, found in carotid arteries & aortic arch
increase CO2=increase HR
Baroreceptors
Sense change in blood pressure, contain nerve endings that respond to stretching of arterial walls, change in set point sends signals to medulla
increase arterial pressure=decrease HR
Proprioceptors
Detect movement, sensory nerve endings in muscles/tendons/joints
increased muscle movement=increase HR
Hormonal control-anticipatory rise
Release of adrenaline prior to exercise, from sympathetic & cardiac nerves helps prepare body for exercise-increase O2 supply to muscles, stimulated SAN=increase in speed & force of contraction
Stoke volume
Volume of blood pumped out of heart in a single contraction (70ml)
Factors affecting stroke volume
Venous return-increase VR=increase SV
Elasticity of cardiac fibres-more stretch=greater contraction force (increased ejection fraction)
Contractility of cardiac tissue-greater contractility=greater contraction force
Starling’s law-increased venous return->greater diastolic filling->cardiac muscle is stretched->more forceful contraction->increased ejection fraction
Stroke volume in response to exercise
increases as intensity increases up to 40-60% of max effort, then plateaus ventricles don’t have enough time to refill
heart rate
Number of times heart beats per min (72bpm)
heart rate in response to exercise
Increases-how much depends on intensity, increases in direct proportion to intensity, regular aerobic training=cardiac hypertrophy &/ bradycardia
Maximal heart rate
Max hr=220-age
Cardiac output
Volume of blood pumped out of the heart per min, cardiac output (Q)=stroke volume(SV) X heart rate(HR)
cardiac output in response to exercise
Increases due to increase in SV&HR - until maximum at rest doesn’t change max cardiac output changes-transport more blood to working muscles-distribution changes
Heart disease-coronary heart disease
coronary arteries become blocked/narrowed by fatty deposits (atheroma) atherosclerosis, arteries become narrowed & cannot deliver O2 to heart - angina,
if atheroma breaks off can cause blood clot-cuts of blood supply leading to heart attack, regular exercise reduces risk
High blood pressure
BP-force exerted by blood against blood vessel walls,
High BP puts extra strain on arteries & heart increases risk of heart attack/heart failure/stroke/dementia
regular aerobic fitness reduces risk
Cholesterol levels
BAD LDL-Low Density Lipoprotein - transport cholesterol in blood tissues
GOOD HDL-High Density Lipoprotein - transport excess cholesterol to liver where its broken down
Regular activity lowers LDL & increases HDL
Stroke
Blood supply to part of brain is cut off
causes cells to die
Ischemic stroke - blood clot (more common)
Haemorrhagic stroke - weakened blood vessel bursts
Regular exercise reduces risk by 27%
Cardiovascular drift
Occurs 20mins after steady state exercise
loss of fluid after 20 mins through sweating
50% of blood vol of plasms - plasma lost from blood
blood becomes more viscous, loss of plasma
blood harder to pump around body-reduces SV, HR must increase to maintain Q
Vascular system
Blood vessels that carry oxygen & nutrients to tissues & take away waste products
Pulmonary
deoxy-blood from heart to lungs
oxy blood from lungs to heart
Systemic
oxy-blood to body
return of deoxy blood to heart
Veins
thinner muscle/elastic layer
wider lumen
valves
Arteries
Thicker elastic layer to cope with higher bp
smaller lumen
smooth inner layer
no valves
Capillaries
1 cell thick, wide enough to fit 1 rbc through at once-slows down blood flow & ensures increase chance of diffusion larger SA, moist to increase rate of diffusion
Flow of blood
Heart→arteries→arterioles→capillaries→venules→veins→heart
Blood pressure during exercise
Increase in systolic pressure-increase SV and force of contraction, decrease in diastolic pressure-vasodilation
Systolic pressure
Force of blood from contraction
Diastolic pressure
Lower pressure as ventricles relax
venous return
Return of blood to right side of heart, increases during exercise-starling’s law
Mechanisms of venous return
Skeletal muscle pump-muscles press on nearby veins when contracting causing pump effects & squeeze blood towards heart
Respiratory pump-changes in pressure in thoracic & abdominal cavities compress nearby veins & assist blood flow back to heart
Pocket valves-blood only flows 1 direction
Gravity
Suction pressure/pump action of heart-smooth muscle squeeze blood
Systolic BP increases-venous return increases
Haemoglobin
Carries 4 oxygen molecules when partial pressure of oxygen in blood is high
Oxyhaemoglobin
transports oxygen to tissue
Myoglobin
Oxygen stored as myoglobin in muscles-has higher affinity for oxygen & will store for mitochondria-aerobic respiration site
Bohr shift
During exercise, S-shaped curve moves to right cause muscles require more oxygen
Oxyhaemoglobin dissociation curve
Dissociation of oxygen from haemoglobin to muscles occurs more readily
increase in BP
Blood & muscle temp increases so oxygen dissociates more readily
Partial pressure of CO2 increases
as CO2 levels rise, oxygen will dissociate quicker due to diffusion theory
pH
more CO2 will lower pH & drop in pH cause oxygen to dissociate quicker
Redistribution of blood
Skeletal muscle require more O2 so blood is directed to them
Blood→brain&kindeys stays same
more blood to heart
more blood to skin, energy is needed to cool body down
Redirecting of blood is
Vascular shunt mechanism
Blood pressure & flow controlled by
Vasomotor centre in medulla oblongata
Control of blood flow
Chemoreceptors-stimulate vasomotor centre, redistribute blood through vasodilation/vasoconstriction
sympathetic stimulation increases-vasodilation occurs & blood flow reduces
sympathetic stimulation decreases-vasodilation occurs
Pre-capillary sphincters
Tiny rings of muscle at opening of capillaries contract-blood flow constricted
Purpose of vasodilation/vasoconstriction
Ensures more blood to skin during exercise to regulate body temp & get rid of heat through radiation, evaporation & sweating removes waste products more blood to heart
increases blood supply
Atrio-venous difference (A-VO2 Diff)
Difference between oxygen content of atrial blood arriving at muscles & venous blood leaving muscles
at rest-A-VO2 diff is low
during exercise-increases, affects gaseous exchange at alveoli so more O2 is taken in & more CO2 is removed
training increases A-VO2 diff as trained performers can extract greater amount of oxygen from blood
A-VO2 diff - adaptations to body resulting in training effect
Increase O2 content in atrial blood due to more RBC/haemoglobin/O2 carrying capacity of blood/increases gaseous exchange at muscles(capillarisation/increase in blood supply/SA/Gaseous exchange at muscles/more myoglobin/Store more O2 in muscle
Less
Respiration
taking in of oxygen & removal of carbon dioxide
What does respiration include
Ventilation
Gas exchange
Transport of gases
Metabolic reactions
Passage of air
nose→pharynx→larynx→trachea→bronchi→bronchioles→alveoli
Gas exchange
Movement of O2 from air into blood & CO2 from blood into air
Movement of gas molecules from an area of high concentration/partial pressure, to an area of low concentration/partial pressure
Adaptation of alveoli
Thin walls-1cell thick, short diffusion path
Extensive capillary network surrounding it
Large surface area-greater uptake of O2
Moist-gases dissolve in moisture helping them to pass across the gas exchange surface
Inhaling
Intercostal muscles contract→ribs move up & out→diaphragm contracts & pulls flat→thoratic cavity gets larger & pressure in lungs decreases to suck air in
Exhaling
Intercostal muscles relax→ribcage moves down & in→diaphragm relaxes & rises to dome shape→thoracic cavity gets smaller→lungs increase→pushing air out
Muscles used at rest during inspiration
Diaphragm external intercostal muscles
Muscles used at rest during expiration
Diaphragm
External intercostal muscles
Muscles used during exercise during inspiration
Diaphragm
External intercostal
Sternocleidomastoid
Scalene
Pectoralis minor
Muscles used during external during expiration
Internal intercostal
Abdominals
Lung volume at rest
Inspire & expire approx 0.5L of air per breath
Tidal volume
Volume of air breathed in OR out per breath increases during exercise
Inspiratory reserve volume
Vol of air that can be forcible inspired after a normal breath
What happens to tidal volume during exercise
Increases
What happens to inspiratory reserve volume during exercise
Decreases
