coordination and response Flashcards
what are the two types of nervous systems
central
peripheral
what does the central nervous system contain
brain and spinal cord
what does the peripheral nervous system contain
all of the nerves in the body
how is information sent through the nervous system
nerve impulses (electrical signals that pass along nerve cells known as neurones)
what is a nerve
a bundle of neurons
what are the 3 main types of neurones
sensory, motor and relay
what is a sensory neurone
carry impulses from sense organs to the central nervous system (brain or spinal cord)
what is a motor neurone
neurones that carry impulses from the central nervous system (brain, spinal cord) to the muscles
what is a relay neurone
neurones are found inside the CNS and connect sensory and motor neurones
characteristics of sensory neurones
long and have a cell body branching off the middle of the axon
characteristics of relay neurones
short and have a small cell body at one end with many dendrites branching off
characteristics of motor neurones
long and have a large cell body at one end with long dendrites branching off it
voluntary vs involuntary actions
voluntary actions involve brain activity to coordinate the response,
where as involuntary actions does not involve the brain as the coordinator of the reaction and you are not aware you have completed it until after you have carried it out
reflex arc steps
stimulus -> receptor -> sensory neurone -> relay neurone -> motor neurone -> effector -> response
sent through electrical impulses
characteristics of reflex actions
1) fast
2) automatic
3) protective
what is a synapse
junction between two neurones
define sensitivity
ability to detect, sense changes in the environment.
ability to detect stimuli and make responses accordingly
define involuntary actions
a response that doesn’t involve thought/decision
what is the function of the cornea
the cornea is a transparent lens refracts (bends) light as it enters the eye
what is the function of the iris
controls how much light enters the pupil
what is the function of the lens
the lens is a transparent disc that can change shape to focus light on the retina
what is the function of the retina
contains light receptor cells (rods and cones)- rods help see black and white and cones help see coloured images
what is the function of the optic nerve
sensory neurone that carries impulses between the eye and the brain
what is the function of the pupil
hole that allows light to enter the eye
what happens to the pupil when it exposed to a lot of light
pupil constricts in order to prevent too much light entering the eye and damaging the retina
what happens to the pupil when it is exposed to dim light
pupil widens so as to allow more light to enter into the retina
what are the two spots in the eye that have the lowest number of rods
yellow spot (fovea)
blind spot
which spot in the eye has most cones
fovea
what is the functions of rods
allows for detection of light of low intensity, converts light to electrical impulses, allows for night vision, gives black and white vision
how does the pupil reflex work in response to low light
-photoreceptors detect change in light
-radial muscles contract
-circular muscles relax
-pupil dilates
-more light is allowed in
how does the pupil reflex work in response to bright light
-photoreceptors detect change in light
-radial muscles relax
-circular muscles contract
-pupil constricts
-less light enters the eye
how does the lens accommodate to view close objects
-ciliary muscles contract
-suspensory ligaments relax
-lens becomes fatter
lens refracts more
how does the lens accommodate to view far away objects
-ciliary muscles relax
-suspensory ligaments contract
-lens become thinner
lens refracts less
where is the “blind spot” located
area where optic nerve attaches to retina
what is a hormone
A hormone is a chemical substance produced by a gland and carried by the blood, which alters the activity of one or more specific target organs
what are all the glands present in the endocrine
pituitary, thyroid, pancreas, adrenal, testes (male), ovaries (female)
what are two hormones the pituitary gland secrets
Human growth hormone (HGH or GH)
Thyroid-stimulating hormone (TSH)
what is the thyroid gland’s job
to control the body’s metabolism
secrets thyroxine
what is the function of the adrenal gland
Adrenal glands produce hormones that help regulate your metabolism, immune system, blood pressure, response to stress
produce adrenaline
what is the function of the pancreas
secretes multiple food digesting enzymes
produces insulin which helps lower blood glucose level and glucagon which helps increase blood glucose level
what is the function of the testes and ovaries
produce testosterone (male sex hormone)
produce and store eggs and make hormones that control your menstrual cycle (oestrogen) and pregnancy
from top to bottom what are all the components of a motor neurone
dendrite
cell body
axon
myelin sheath
nodes of Ranvier
the nucleus of the myelin sheath
nerve ending
from top to bottom what are all the components of a relay neurone
dendrite
cell body
axon
pre-synaptic terminal
from top to bottom what are all the components of a sensory neurone
receptor cell
myelin sheath
axon
cell body
which two parts of the eye refract light
cornea, lens
what does adrenaline do to the body
increase the blood glucose level
increased rate of respiration in muscles
increased heart rate
increased breathing rate
diverting blood flow to muscles
dilating pupils
when radial muscles contract what happens to the pupil
when radial muscles in iris contract the pupil dilates
when circular muscles in the iris contract what happens to the pupil
when circular muscles contract the pupil constricts
how does the lens change to be able to accommodate viewing of up close objects
lens becomes thicker to be able to refract the light rays and make them converge at the retina
how does the lens change to accommodate
becomes thinner to view far away objects
becomes thicker to view close objects
how does the lens accommodate to the viewing of objects further away
become thinner to be able to converge light to the retina from far away
what part of the eye is sensitive to light
retina
define sensitivity
ability to detect changes in the environment stimuli react/change in accordance
how do cones allow the human eye to see light
cones respond to different wavelengths, converts light into electrical impulses, optic nerve accumulates the data and sends it to brain for the brain to interpret it.
explain why extra glucose needs to be converted to glycogen
glucose is soluble, glycogen is insoluble
glucose in blood would lower water potential
causing hyperglycemia
name 3 sense organs and the stimulus they respond to
eye - light
ears - sound
nose - smells
what are the advantages of simple reflexes
fast, automatic and protective/defensive
voluntary vs involuntary
voluntary involves brain decision making
voluntary actions are slower
voluntary actions are not automatic
what are the 2 parts of the eye that control the direction of the light rays
cornea and lens
where in the eye is the image formed
retina
where is the cell body in the sensory neurone
ganglion
where is the cell body in the relay neurone
gray matter (spinal chord)
what prevents the leakage of the impulse
myelin sheath
what are the 2 effectors in the body
muscles
glands
which neurone stimulates effectors
motor neurone
what is the pathway of light entering the eye
cornea -> aqueous humour -> pupil -> lens -> vitreous humour
