Tolerance Limits
Name one factor that organisms have a tolerance limit for.
Draw the Stimulus-Response Model, including the types of neurons that are involved.
See Board
Draw a diagram to illustrate the organisation of the human nervous system.
See Board
Name the process used by organisms to regulate their BGL.
Glucoregulation
Explain what a sensory receptor is, and name a specific type of sensory receptor.
Specialised cells that detect stimuli both inside and outside of the body. Specific Types: Chemoreceptor, Mechanoreceptor, Nociceptor, Thermoreceptor, Photoreceptor
Name the three types of neurons found in the human nervous system and describe their function.
Sensory Neuron - Transmit information from a receptor to the CNS (brain).
Interneuron - Transmit information between sensory and motor neurons in the CNS.
Motor Neuron - Transmit information from the CNS (brain) to effectors.
Define: Tolerance Limit
The maximum and minimum amount of a given factor a species or organism can tolerate before it becomes too hard to maintain life processes.
Draw a specific example of the Stimulus-Response Model, including the types of neurons that are involved.
Various
Which one of the following nerve pathways represents the reflex response to the stimulus of stepping on a sharp object?
J. Receptor -> Motor Nerve -> Spinal Cord -> Sensory Nerve -> Muscle in Foot
K. Receptor -> Motor Nerve -> Brain -> Sensory Nerve -> Muscle in Leg
L. Receptor -> Sensory Nerve -> Brain -> Motor Nerve -> Muscle in Foot
M. Receptor -> Sensory Nerve -> Spinal Cord -> Motor Nerve -> Muscle in Leg
M. Receptor -> Sensory Nerve -> Spinal Cord -> Motor Nerve -> Muscle in Leg
Explain a consequence that may occur if an organism's body temperature becomes dysregulated.
Below TL: The rate of enzyme-catalysed reactions are too slow.
Above TL: Denaturation of enzymes, decreasing the rate of enzyme-catalysed reactions.
Define: Negative Feedback
Caffeine is a drug that reduces the effect of the neurotransmitter adenosine. Adenosine is responsible for inducing sleep in a healthy person. Caffeine prevents adenosine from binding to receptors in the hypothalamus.
Caffeine
J. decreases the amount of time it takes for a healthy person to fall asleep.
K. binds to the active site of adenosine.
L. reduces the number of nerve impulses triggered by adenosine.
M. acts as an inhibitor that prevents the release of adenosine.
L. reduces the number of nerve impulses triggered by adenosine.
Explain a consequence that may occur if an organism's carbon dioxide concentration becomes dysregulated.
Below TL: Hypocapnia and Respiratory Alkalosis (Increase pH of the Blood). Symptoms may include: Tingling sensation in the limbs, abnormal heartbeat, muscle cramps, dizziness, fainting, and seizures.
Above TL: Hypercapnia and Respiratory Acidosis (Decrease pH of the Blood). Symptoms may include: Breathlessness, rapid breathing, headache, inflammation, disorientation, and loss of consciousness.
Hypothermia in humans occurs when the core body temperature drops below 35 degrees Celsius. As core body temperature decreases, the rate of enzyme-controlled metabolic reactions decreases, resulting in a further decrease in core body temperature.
Hypothermia
J. demonstrates negative feedback, because the response inhibits the initial stimulus.
K. demonstrates negative feedback, because the response does not inhibit the initial stimulus.
L. does not demonstrate negative feedback, because the response inhibits the initial stimulus.
M. does not demonstrate negative feedback, because the response does not inhibit the initial stimulus.
M. does not demonstrate negative feedback, because the response does not inhibit the initial stimulus.
Describe the role of neurotransmitters in the synapse. (4 Marks)
A nerve impulse stimulates the release (exocytosis) of the neurotransmitter into the synapse (1). Neurotransmitter molecules diffuse across the synapse (or synaptic cleft) (1) and bind to complementary receptors (1) in the membrane of the adjacent (or postsynaptic) neuron. This enables the nerve impulse (message) to be passed from one neuron to the next (1).