BIOH111 FINAL EXAM QUESTIONS AND ANSWERS WITH
COMPLETE SOLUTIONS GRADED A++ LATEST UPDATE
Events of step 1 release of acetylcholine
1. Stimulates voltage-gated channels to open allowing calcium to flow through
2. Calcium entering stimulates the synaptic vesicles to undergo exocytosis with the
plasma membrane
3. Acetylcholine diffuses across the synaptic cleft between the motor neurons and the
motor end plate
Events of step 2 activation of acetylcholine receptors
1. Binding of acetylcholine to the receptor on the motor end plate opens an ion channel
2. sodium can flow across the membrane once the channel is open
Events of step 3 production of muscle action potential
1. Inflow of positively charged sodium down its electrochemical gradient makes muscle
fibres more positively charged
2. Positive charge triggers muscle action potential
3. Nerve impulse propagates along the sarcolemma
4. Sarcoplasmic reticulum releases stored calcium into the sarcoplasm and the muscle
fibre contracts
Event of step 4 termination of acetylcholine activity
Once acetylcholine binds it is rapidly broken down by acetylcholinesterase which
prevents subsequent activation of ACh receptor
, Neurotransmitters
Acetylcholine, dopamine, epinephrine, GABA, substance P
Acetylcholine
Activates muscle action, learning and memory
Dopamine
Pleasure and addiction, regulating skeletal muscle tone
Epinephrine (adrenaline)
Increases blood flow and heart rate, awareness
Substance P
Increases pain awareness, vasodilation
GABA
Contributes to muscle control, regulates behaviour and cognition
Sensory receptor types
Mechanoreceptor, thermoreceptor, photoreceptor, Osmoceptor chemoreceptors
Mechanoreceptors
respond to touch, pressure, vibration, stretch, and itch
Thermoreceptors
respond to changes in temperature
Osmoreceptor
detects osmotic pressure of body fluids
Chemoreceptors
respond to chemicals
Photoreceptors
COMPLETE SOLUTIONS GRADED A++ LATEST UPDATE
Events of step 1 release of acetylcholine
1. Stimulates voltage-gated channels to open allowing calcium to flow through
2. Calcium entering stimulates the synaptic vesicles to undergo exocytosis with the
plasma membrane
3. Acetylcholine diffuses across the synaptic cleft between the motor neurons and the
motor end plate
Events of step 2 activation of acetylcholine receptors
1. Binding of acetylcholine to the receptor on the motor end plate opens an ion channel
2. sodium can flow across the membrane once the channel is open
Events of step 3 production of muscle action potential
1. Inflow of positively charged sodium down its electrochemical gradient makes muscle
fibres more positively charged
2. Positive charge triggers muscle action potential
3. Nerve impulse propagates along the sarcolemma
4. Sarcoplasmic reticulum releases stored calcium into the sarcoplasm and the muscle
fibre contracts
Event of step 4 termination of acetylcholine activity
Once acetylcholine binds it is rapidly broken down by acetylcholinesterase which
prevents subsequent activation of ACh receptor
, Neurotransmitters
Acetylcholine, dopamine, epinephrine, GABA, substance P
Acetylcholine
Activates muscle action, learning and memory
Dopamine
Pleasure and addiction, regulating skeletal muscle tone
Epinephrine (adrenaline)
Increases blood flow and heart rate, awareness
Substance P
Increases pain awareness, vasodilation
GABA
Contributes to muscle control, regulates behaviour and cognition
Sensory receptor types
Mechanoreceptor, thermoreceptor, photoreceptor, Osmoceptor chemoreceptors
Mechanoreceptors
respond to touch, pressure, vibration, stretch, and itch
Thermoreceptors
respond to changes in temperature
Osmoreceptor
detects osmotic pressure of body fluids
Chemoreceptors
respond to chemicals
Photoreceptors
