ANIMAL RESPONSES Flashcards
Function of cerebrum
Largest part of human brain
Responsible for elements of the nervous system (e.g. conscious thoughts, imagination)
2 hemispheres, joined by corpus collosum
Function of cerebellum
Folded surface smaller than cerebrum
Contains over half of the nerve cells in the brain
Responsible for coordination, balance
Processes sensory information from retina, joints + spindle fibres
Function of medulla oblongata
Links brain + spinal cord
Controls non-skleletol muscles
Therefore coordinates + controls involuntary movements such as breathing + heart rate
Controls cycles (e.g. respiratory)
Function of hypothalamus
Main control system of autonomic nervous system
Receives sensory input from temperature receptors + osmoreceptors
Initiates automatic responses to regulate temperature and blood water potential
Regulates pituitary gland
Function of pituitary gland
Posterior lobe linked by hypothalamus
Anterior pituitary gland produces six hormones (e.g. FSH)
Posterior pituitary stores + releases hormones produced by hypothalamus (e.g. ADH)
Function, target tissues + effect, number of neurones (myelinated or not) of somatic neurone
Controls conscious activities (e.g. movements, reflexes)
Skeletal muscles
Excitatory- muscle contract
One, myelinated
Function, target tissues + effect, number of neurones (myelinated or not) of autonomic neurone
Controls homeostasis and mechanisms, regulates internal organs
Smooth and cardiac muscles (+ some glands)
Excitatory or inhibitory- muscle contracts
2 (linked by ganglion outside spinal cord)
Mostly non-myelinated
Compare the functions of sympathetic and parasympathetic nervous system
Parasympathetic more active during sleep and relaxation
Sympathetic more active at times of stress
Have antagonistic effects
Structure comparison sympathetic and parasympathetic
Position of ganglion
Length of pre-ganglionic neurone
NT
Outside spinal cord, within target tissue
V short, varies
Noradrenaline, ACH
Neuromuscular junctions
- AP causes v-gated Ca2+ channels to open, Ca2+ diffuses in
- Ca2+ causes synaptic vesicle to move + fuse with the presynaptic membrane + release ACH into cleft (exocytosis)
- ACH diffuses across cleft + binds to receptors on sarcolemma= Na+ open
- Na+ floods in= depolarisation down t-tubules
- CA2+ channels open + diffuse out sarcoplasmic reticulum
- Ca2+ binds with proteins in muscles= contraction
- Acetylcholinesterase breaks down ACH so contraction only occurs with an impulse
What is a reflex
Rapid + involuntary
Process of a reflex
Stimulus detected by receptor
Impulse- sensory- spinal cord
Either passes directly to the motor neurone or to a relay then motor
If relay- synapses with other CNS neurones= consisted awareness
Blinking reflex
- sensory neurone from cornea seeds impulse to brains stem
- synapse with unmyelinated relay neurones
- motor cause facial muscles to contract= blink
Knee jerk reflex
- patella tendon stretches, stretch receptors detect change in length
- sensory neurone stimulates motor
- extensor muscle contracts + straightens leg
- at the same time- impulse from sensory- relay= relaxes flexor muscle
Fight or flight response
Physiological changes
Increased HR
Pupils dilate
Erector pili muscles in skin contract
Ventilation and depth increases