Co-ordination and response Humans Flashcards
Topic 2 J.3
the 2 different control systems in humans
nervous system
hormonal system
what is the hormone system also known as
endocrine system
what do the 2 systems do
coordinate a suitable response to stimuli
what do the hormonal and nervous system allow for
allow us to respond to changes that happen in our surroundings and regulate body functions to them
Information is sent through the nervous system as
electrical impulses
electrical signals pass along ____ cells known as
nerve cells
neurons
impulses travel along the neuron at what speed
super high speeds
why do impulses travel the neuron at fast speeds
This allows rapid responses to stimuli. (reflexes)
The nervous system coordinates the activities of ____ _____
sensory receptors and effectors
The nervous system is used to control functions that need_____responses
rapid or instant
information is sent through the endocrine system as ____ known as _____
chemical substances
hormones
hormones are carried by the
blood
hormones transmit information from_ to _ in order to
one part of the body to the other
bring about a change
hormones alter the activity of
a specific target organ
hormones are produced by
endocrine glands
endocrine glands that produce hormones in animals are known as the
endocrine system
a gland is
a group of cells that produces and releases one or more substances
nervous system is made of
nerves
endocrine system is made of
glands
endocrine system has a ____ message type
chemical hormone
nervous system uses ____ as messengers
electrical impulses
speed of action for nervous system
very fast
speed of action for endocrine system
slower
duration of effect of nervous system
Short - until the nerve impulse stops
duration of effect of endocrine system
Long - until the hormone is broken down in the body
the human CNS nervous system consists of (2)
brain and spinal cord
human peripheral nervous system consists of
all of the nerves in the body ( with sensory and motor neurones)
what is a nerve
A bundle of neurones is known as a nerve
nerves spread out from the central nervous system to
all the other regions of the body and sense organs
the CNS acts as a
central coordinating centre for the impulses that come in from any part of the body
pathway through nervous system ( order of stimuli, effector recepetor …) (7)
stimulus
sensory neurone
relay neurone
motor
neurone
effector
response
a stimulus is recieved by
a sensory neurone (receptor)
are receptors specialised to detect a particlar stimuli or no
most are yes
When a receptor is stimulated, it produces
electrical impulses
the impulses travel along a _______ _____ to the central nervous system
sensory neurone
These impulses then travel along a sensory neurone to the ___ ____ ____
central nervous system
In the CNS, the impulses are passed on to a
relay neurone
The relay neurone links to a_____ ______ along which the impulses travel until they reach the ____
motor neurone
effector
the effector is what ___
and it may be a ___ or ___
carries out the response
a muscle or gland
do neurones come into direct contact with each other
no
what is a synapse
Where the dendrites of two neurones meet (to make a connection between the neurones) a junction known as a synapse is formed
at a synapse, there is a tiny ___ between the neurones
gap
the very small gap between the neurones in a synapse is called
the synaptic cleft or gap
Electrical impulses can/cannot travel directly from one neurone to the next due to the synaptic cleft
cannot
as the electrical signals can’t pass the synaptic cleft, it is …
converted to a chemical signal that can cross the synaptic cleft
The chemical signalling molecules used to transfer the signal between neurones at a synapse are known as
neurotransmitters
what are neurotransmitters
The chemical signalling molecules used to transfer the signal between neurones at a synapse
once neurotransmitters cross the synaptic cleft and meet the neurone on the opposite side, what happens to the signal
it is converted back to an electrical impulse which can pass along the neurone
how is an impulse passed across a synapse
- The electrical impulse travels along the axon of the first neurone
- This triggers the end of the presynaptic neurone to release chemicals called neurotransmitters from vesicles
when an impulse is passed across a synapse, the vesicles …
fuse with the presynaptic membrane, releasing their contents into the synaptic cleft
what do neurotransmitters do
they diffuse across the synaptic cleft and bind with receptor molecules on the membrane of the second neurone
when neurotransmitters diffuse across the synaptic cleft, what does this stimulate
the second neurone to generate an electrical impulse which travels down the second axon
when an impulse is passed across a synapse and the second neurone has generated an electrical impulse what happens to the neurotransmitters
they are destroyed to prevent continued stimulation of the second neurone (otherwise the neurotransmitters would cause repeated impulses to be sent
Synapses ensure that impulses only travel in
one direction
why do synapses need to ensure that impulses only travel in one direction
it avoids the confusion that would be caused within the nervous system if impulses were able to travel in both directions
a reflex response is
an involuntary response
does the reflex response involve the conscious part of the brain as the coordinator
no
for a reflex response, you only become aware of it …
only after the response has been carried out
reflex responses are ( speed and automatic or not)
fast and automatic
why do reflex responses need to be fast and automatic
this helps to minimise damage to the body and aids survival
examples of a reflex response
blinking, coughing, pain withdrawal
a reflex arc is
is the pathway of a reflex response
(specifically, the pathway taken by electrical impulses as they travel along neurones)
reflex arc when touching a hot object. (6)
- the pain is detected by a pain/touch receptor in the skin
- a sensory neurone sends electrical impulses to the spinal chord ( coordinator)
- An electrical impulse is passed to a relay neurone in the spinal cord
- A relay neurone synapses with a motor neurone
- A motor neurone carries an impulse to a muscle in the finger (the effector)
- When stimulated by the motor neurone, the muscle will contract and pull the finger away from the hot object (the response)
the eye is a highly specialised ___ organ
sense
eye contains ____ cells that allow us to detect the stimulus of ___
receptor
light
the retina of the eye contains 2 types of receptor cells ( what are they)
- Receptor cells that are sensitive to light, known as rods
- receptor cells that can detect colour, known as cones
STRUCTURE OF EYE
cornea is
the clear outer layer of the eye that helps to focus light onto the retina
STRUCTURE OF EYE
iris controls
controls how much light enters the pupil
STRUCTURE OF THE EYE
lens is
transparent disc that can change shape to focus light onto the retina
STRUCURE OF THE EYE
retina
contains light receptor cells – rods
and colour detector cells - cones
STRUCTURE OF THE EYE
Optic nerve
sensory neurone that carries impulses between the eye and the brain
STRUCTURE OF THE EYE
pupil
hole that allows light to enter the eye
STRUCTURE OF THE EYE
Conjunctiva
a clear membrane that covers the white of the eye and the inside of the eyelids; it lubricates the eye and provides protection from external irritants
STRUCTURE OF THE EYE
ciliary muscle
a ring of muscle that contracts and relaxes to change the shape of the lens
STRUCTURE OF THE EYE
Suspensory ligaments
ligaments that connect the ciliary muscle to the lens
STRUCTURE OF THE EYE
Sclera
the strong outer wall of the eyeball that helps to keep the eye in shape and provides a place of attachment for the muscles that move the eye
STRUCTURE OF THE EYE
Fovea
a region of the retina with the highest density of cones (colour detecting cells) where the eye sees particularly good detail
STRUCTURE OF THE EYE
blind spot
the point at which the optic nerve leaves the eye, where there are no receptor cells
The way the lens brings about fine focusing is called
accommodation
the lens is elastic and its shape can be changed when
the suspensory ligaments attached to it become tight or loose
the changes to the lens are brought about by
the contraction or relaxation of the ciliary muscles
when an object is close up, the cilliary muscles
contract
when an object is far away, the cilliary muscles
relax
when the cilliary muscles contract because an object is close up, what happens to the suspensory ligaments and what does it lead to
they loosen which stops them from pulling on the lens to become fatter and light is refracted more
when the cilliary muscles relax because an object is far away, what happens to the suspensory ligaments and what does it lead to
they tighten which means they pull on the lens, causing it to become thinner and light is refracted less
what is the pupil reflex
a reflex action carried out to protect the retina from damage
in dim light, the pupil ___ in order to ___
dilates
allow as much light into the eye as possible to improve vision
in bright light, the pupil ____ in order to ____
constricts
prevent too much light from entering the eye and damaging the retina
what is the largest sense organ
the skin
what is a cooling mechanism in humans (3)
Vasodilation
sweating
flattening of hairs
when you are very hot, what happens
when lots of sweat is produced , and it evaporates, transferring energy from your skin to the environment to cool you down.
what is vasodilation
blood vessels in the skin surface widen to allow more blood to flow near the surface so that it can transfer more energy into the surroundings to cool you down
what happens to hairs during vasodilation
they lie flat
what happens when you’re very cold (sweat)
very little sweat is produced
what is vasoconstriction
blood vessels narrow near the surface of the skin and so less blood flows near the surface, so less energy is transferred to the surroundings.
what happens during vasoconstriction
blood vessels near the surface of the skin constrict so less blood flows near the surface, so less energy is transferred to the surroundings.
you shiver which increases rate of respiration which transfers energy to warm the body. exercise does the same
what happens to hairs in vasoconstriction
hairs stand on end to trap an insulating layer of air, which helps keep you warm
does shivering occur in vasoconstriction or dilation and why
vasoconstriction because it increases rate of respiration which transfers energy to warm the body.
other than shivering, what increases rate of respiration
exercise
what are temperature receptors known as
thermoreceptors
where are thermoreceptors found
skin and hypothalamus (brain)
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
hormones are chemicals that transmit. ____ without ____
information from one part of the organism to another and bring about a change
important hormones in humans (5)
- adrenaline
- insulin
- testosterone
- progesterone
- oestrogen
adrenaline is known as the
‘fight or flight’ hormone
why is adrenaline known as the ‘fight or flight’ hormone
because it is produced in situations where the body may be in danger
what does adrenaline cause (4)
- An increase in heart rate and breathing rate
- Diverting blood flow towards muscles
- Dilation of the blood vessels inside muscles
- Breaking down of stored glycogen to glucose
what response does adrenaline prepare you for ( remember fight or flight)
movement ( fight or flight)
what does an increase in heart & breathing rate from adrenaline ensure
glucose and oxygen can be delivered to muscle cells (and carbon dioxide can be taken away from muscles cells) at a faster rate
what does diverting blood flow towards muscles from adrenaline ensure
increased supply of the reactants of respiration
what does Dilation of the blood vessels inside muscles from adrenaline ensure
more blood can circulate through them, supplying more glucose and oxygen
what does Breaking down of stored glycogen to glucose from adrenaline ensure
higher blood glucose concentration for increased respiration in muscle cells (providing greater energy for movement)
where is adrenaline found
adrenal glands
what does insulin do
helps control blood sugar levels
where is insulin made/ released
pancreas
effects of insulin
stimulates liver to turn glucose into glycogen for storage
where is testosterone found
testes
role of testosterone
main male sex hormone
effects of testosterone
promotes male secondary characteristics
progesterone is found in the
ovaries
progesterone does what
supports/maintains pregnancy
effects of progesterone
maintains lining of uterus
oestrogen is found in the
ovaries
oestrogen role is
main female sex hormone
effects of oestrogen
controls menstrual cycle and promotes secondary sexual characteristics
ADH stands for
anti diuretic hormone
ADH is found in the
pituitary gland
ADH does what
controls water content
ADH effects
increases permeability of kidney tubules to water
FSH is released in the
pituitary gland
role of FSH
follicle stimulating hormone
effects of FSH
auses egg to mature in ovary and stimulates egg to produce oestrogen
LH found in
pituitary gland
LH stands for
leutanising hormone
LH role
female sex hormone
LH effects
stimulates release of egg from ovary
what is a hormone
a chemical messenger
from where re hormones secreted
glands
what are the 2 muscles in the eye
radial and circular muscles
What does accomodation cause the lens to do
change shape
accomodation allows
eye to focus on objects close or far away from the eye
accomodation is controlled by (2)
cilliary muscles and suspensory ligaments
purpose of pupil reflex
protects retina from damage
how does the pupil reflex work in dark conditions
radial muscles contract while the circular muscles relax, pulling the lens backwards and dilating the pupil, allowing more light to enter
how does the pupil reflex work in bright conditions
the circular muscles contract, and the radial muscles relax, causing the iris to increase in size and constricting the pupil, preventing too much light to get in the eye
when focusing on an object that is far away, what do the cilliary muscles and suspensory ligaments do
cilliary muscles relax while the suspensory muscles pull tight to make the lens thinner and focus the light
when focusing on an object that is near, what do the cilliary muscles and suspensory ligaments do
ciliary muscles contract while suspensory ligaments slacken, causing lens to become fatter and focus the light ( light is refracted more by lens to focus on near objects)
do suspensory ligaments contract and relax
NO they tighten and slacken
oestrogen inhibts the production of ____ and ___ in the ____ ___
LH & FSH
PITUITARY GLAND
Progesterone inhibits ___ and ___
LH & FSH
if fertilisation doesn’t happen what happens to progesterone levels
they drop, menstruation will start
FSH stimulates
ovaries to release oestrogen
LH stimulates
ovary to producen progesterone
