Animal Responses Flashcards
what do receptors and effectors do?
receptors: detect stimuli
effectors: bring about a response to the stiumuld
receptors communicate with eachother through?
nervous system, hormonal system or both.
the nervous system is split into:
the central NS and the peripheral NS
CNS is made up of
brain and the spinal cord
the PNS is made up of
the neurones that connect the CNS to the rest of the body.
the PNS is split into
the somatic NS and the autonomic NS
somatic NS function
controls conscious activities
autonomic NS functions
controls unconscious activites like digestion
autonomic NS is divided into
sympathetic NS and the parasympathetic NS
sympathetic NS function
controls fight or flight response by releasing noradrenaline
parasympathetic NS funciton
controls rest and digest response and release acetylcholine
location and function of the hypothalamus?
beneath the middle part of the brain
maintains body temperature at the normal level
pituitary gland location and function
beneath the hypothalamus
controlled by the hypothalamus - stimulates other glands to release hormones and releases 6 different hormones.
cerebrum structure and function
largest part of brain that is divided into 2 hemispheres
has a thin outer layer called the cerebral cortex
involved in vision, hearing, learning and thinking
medulla oblongata location and function
base of brain top of the spinal cord
automatically controls heart and breathing rate
cerebellum location and function
underneath the cerebrum abck of head
muscle coordination, posture and coordination of balance
what is a reflex
where the body responds to a stimulus without making a conscious decision to respond.
rexlexes help organisms to
avoid damage to the body because they are rapid.
blinking reflex - how does it work?
4 parts
- sensory nerve endings in the cornea are stimulated by touch
- a nerve impulse is sent along the sensory neurone to a relay neruone in the CNS
- the impulse is then passed from the relay to motor neurones.
- the motor neurones send impulses to effectors (orbicularis oculi muscles) that move the eyelids contract causing them to close quickly and prevents the eye from being damaged.
knee jerk relex - how does it work?
3 points
- stretch receptors in the quadriceps muscle detect that the muscle is being stretched.
- a nerve imoulse is passed along a sensory neurone which communicates directly with a motor neurone in the spinal cord
- the motor neurone carries the nerve impulse ot the effector causing it to contract so the lower leg moves forward quickly.
FIGHT OR FLIGHT
when an organism is threathened it responds by
preparing the body for action - fight or flight.
FIGHT OR FLIGHT
nerve impulses from the sensory neurones arrive at?
the hypothalamus which activates both hormonal and nervous systems.
FIGHT OR FLIGHT
the pituitary gland is stimulated to release
the hormone ACTH which causes the cortex of the adrenal gland to release steroidal hormones.
FIGHT OR FLIGHT
the sympathetic nervous system is activated and triggers the release of
adrenaline from the adrenal medulla
FIGHT OR FLIGHT
adrenaline has the 5 following effects:
- heart rate increases - blood is pumped around the body faster
- muscles around the bronchiole relax - deeper breaths
- glycogen converted into glucose - more available for muscles to respire
- muscles in the artrioles supplying the skin and gut constrict so arterioles supporting the heart and lungs dilate for more oxygen.
- erector pili muscles in the skin contract to make hairs stand - animal looks bigger.
HEART RATE
the NS helps to control the heart rate: first step?
SAN generates electrical impulses that cause the cardiac muscles to contract
HEART RATE
the rate at which the SAN fires is controlled by
the medulla oblongata in the brain (unconscious)
HEART RATE
animals need to alter their heart rate to?
respond to internal stimuli
HEART RATE
stimuli are detected by?
pressure and chemical receptors
HEART RATE
what are baroreceptors
pressure receptors in the aorta and vena cava which are stimulated by high and low blood pressure
HEART RATE
what are chemoreceptors?
chemical receptors in the aorta, carotid artery and themedulla which monitor oxygen, carbon diocide and pH levels in the blood.
HEART RATE
final step?
electrical impulses from receptors are sent to the medulla along the sensory neurones - the medulla processes the information and sends impulses to the SAN along the motor neurones.
HEART RATE
what happens when there is high blood pressure?
baroreceptors detect high blood pressure - impulses are sent to the medulla which sends impulses along the vagus nerve, which secretes acetylcholine and binds to the receptors on the SAN. cardiac muscles slow heart rate down to reduce pressure back to normal.
HEART RATE
what happends when there is low blood pressure?
baroreceptors detect low blood pressure - impulses are sent to the medulla which sends impulses along the accelerator nerve, which secretes noradrenaline and binds to the receptors on the SAN. cardiac muscles increase heart rate down to increase pressure back to normal.
HEART RATE
what happends when there is high blood o2 / low co2 / high pH
chemoreceptors detect chemical changes in blood - impulses are sent to the medulla, which sends impulses along the vagus nerve, secretes acetylcholine which binds to the receptors on the SAN.
HEART RATE
what happends when there is low blood o2 / high co2 / low pH
chemoreceptors detect chemical changes in blood - impulses are sent to the medulla, which sends impulses along the accelerator nerve, secretes noradrenaline which binds to te receptors on the SAN.
HEART RATE
the hormonal system also helps to control heart rate by
releasing adrenaline - binds to specific receptors in the heart and causes the cardiac muscles to contract more frequently and with more force so heart rate increases and heart pumps more blood.
