RECEPTORS Flashcards
Co2 level rise
Detected by chemoreceptors in aorta
More frequent impulses sent to medulla
More frequent impulses from accelatory center in medulla to SAN node via sympathetic nerve
More frewuent impulses from SA node across artery
Heart rate increases
Decrease blood pressure
Detected by baroreceptor in walls of aorta
More frequent impulses sent to medulla
More frequent impulses frim accelatory center in medulla to SA node via sympathetic nerve
Increases frequency of imoulses from SA node across atria
Heart rate incereases
Increase blood pressure
·Detected by baroreceptors in walls of aorta
More frequent impulses sent to medulla
More frequent impulses from inhibitory center in medulla to SD node via
Parasympathetic nerve
·Decreases frequency of impulses from SD node across atria
· Heart rate decreases
Control of hear rate
SN node sends electrical activity across both atria
Both atria contract
layer of nonconductive tissues prevents wave reaching ventricles
wave of electrical activity reaches to atrio venticulst node
delay allowing atria to empty fully of blood
wave of electrical activity sent from atrioventicular node
Down the bundle of His to the base of the ventricles
Up the Purkinje fibres
Causing ventricles to contract from the apex of the heart upwards
Hear controls and coordinates regular contraction if atria & ventricle
SaN->AVN-> Bundle of His
electrical activity
Atia contract
Non-conducting tissues between atria I ventricles
Delay at an ensures atra empty
ventricles contract from apex upwards
Rods
Evenly distributed throught macula
Sensetive to all wavelength of light (Rhodopsin)
Hugh visual sensitivity to low levels of light intensity
Low visual acuity image unclear due to several rods sharing single bipolar neuron
Cones
Densely packfed in fovea
Cone detects soecfici wavelenth of light
Each come cell is sensitive to specficc wavelength
Iodopsin less sensitive
High visual accuity so sharo image as each cone cell connected with a single bipolar neuron
Rhodopsin
Pigments absors all wavelength of light
Lower resolution
Iodopsin
Absorbs specific wavelenth of light
Higher resolution
Rodss
low visual acuity as several cells connected to one bipolar neuron.
light falls on several rod cells will only generate 1 impulse to brain.
Brain can’t distinguish between separate light sources that generated them
highly sensitive to low light intensities.
Stimulation of several rods result in net to reach threshold in bipolar neuron in low interity
Retinal convergence leads to spital summation
Coness
High visual acuity synapses with an individual bipolar neuron
2 cones generate 2 electrical impulses to brain so it can distinguish
between light sources that generated them.
Brain interprets this as 2 separate points of light
·Temporal summation
Pacinian corpuscles
Shape of corpuscle changed
Stretch mediated Na+ channels in the neurone membrane open
·Na+ diffuse in and depolarise membrane leading to generator potential
· Greater pressure
·More strech mediated Na+ channel open
More difusion of Na+ ions
· Bigger generator potential
It threshold potential reached
An action potential develops & is transmitted along the sensory
neuron
