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1.23.1.14 - Introduction to the Cardiac System - Coggle Diagram
1.23.1.14 - Introduction to the Cardiac System
heart disease
common in small animal and equine
disease often involves valve degeneration
heart becoming incompetent
disease of the heart muscle
heart doesn't contract well
heart doesn't fill up with blood
heart disease does not always result in failure
heart failure is a syndrome
heart fails to deliver blood
heart doesn't meet metabolic requirements of tissues
cardio-respiratory system functions
transport
carbon dioxide
nutrients
oxygen
waste
heat
hormones
homeostasis
pH
osmolarity
electrolytes
infection
other
generate pressure
renal filtration
reproduction
the mammalian heart
right heart pumps deoxygenated blood
prevents admixture of oxygenated and deoxygenated blood
left heart pumps oxygenated blood
dual chambered
forward in throax
protected by muscle mass of forelimb
different in non mammals
embryological development
heart starts as one chamber then divides
cardiac cycle
systole vs diastole
systole = contraction
diastole = relaxation
ventricular systole
contraction of ventricles
results in cardiac output
atrioventricular valves close
'lub'
ventricular diastole
results in ventricular filling
semi-lunar valves close
relaxation of ventricles
'dub'
regulation of cardiovascular function
considerations
electrical activity
ECG
contractile function control
autonomic nervous system
hormonal mechanisms
systemic
local
regulation of the vasculature
autoregulation
local blood flow regulation
ability of an organ to maintain constant blood flow despite changes in perfusion pressure
autonomic nervous system
hormonal mechanisms
local
systemic
heart as a pump
cardiac output
volume delivered into the circulation per minute
stroke volume
volume delivered by the ventricle per beat
other pumping mechanisms
venous
distribution of blood within the heart and vasculature
maintenance of unidirectional flow in vital organs
cardiac valves
vascular constriction and dilation
veins
arteries
vascular valves
venous return
deoxygenated blood is returned to the heart
diastolic cardiac volume is important for cardiac output
important controlling factors
sympathetic nervous system
blood volume
muscle (respiratory) pump
vascular system
veins
returns to heart
portal veins
between 2 capillvary beds
arteries
from the heart
capillaries
sites of diffusion
regulation of cardiovascular function
cardiac output and systemic vascualr resistance
what happens in the capillary beds
capillary diffusion
tissue fluid production
extracellular vs intracellular fluid
the importance of maintaining blood pressure
avian CVS
birds have an effective CVS
cope iwth high metabolic demands
important for oxygen delivery and thermoregulation
large cardiac size
compared to body weight
can in some species generate very fast heart rates
birds have relatively high cardiac output
increased heart rate = increased cardiac output
heart size fluctuates
increases prior to migration
ventricles
left ventricular wall 3x thicker than right
empty nearly completely on each cardiac cycles
cardiac topography
heart located on ventral midline
enclosed by right and left lobes of liver
birds have NO diaphragm
valves
left AV valve has 3 leaflets
right AV valve
muscular flap
no chordae tendinae
avian renal portal system
receives blood from caudal body
drugs injected into hind limbs are metabolised before general circulation
portal flow regulated by portal valves
continuous with caudal mesenteric vein
blood from GIT may bypass liver
drains hind limbs
cardiac function
heart failure
when things go wrong
how drugs can support cardiac function
physiological effects
altitude
cardiac parasites
imaging the heart
cardiac ultrasound = echocardiography
fish, amphibians and reptiles
different to nn mammals
theory of recapitulation
embryological paralellism
evolution