The Nervous System Flashcards
A change in a membrane potential from +30mV to -70mV is an example of:
Repolarisation
A threshold potential is:
The point at which there is an explosive increase in Na+ permeability
Graded Potentials:
Two Answers
- Are local changes in membrane potential that occur in varying degrees of magnitude
- Serve as short distance signals
Myelinated axons conduct impulses much faster because:
Four reasons
- The myelin insulates the axon
- Channels only have to open at the nodes
- Voltage is not lost through along myelinated areas
- Saltatory conduction
Permeability of which ion is affected by a positive feedback mechanism once threshold is reached?
Sodium
The relative refractory period occurs after the action potential is complete because of the:
(Two Reasons)
- Lingering inactivation of the voltage gated Na+ channels
- Slowness of the voltage gated channels
The trigger zone of a neuron:
Three Answers
- Precedes the axon
- Is located in the Hillock
- Contains voltage gated channels
Sequence the following events correctly:
- Neurotransmitter diffuses across cleft
- Calcium induces exocytosis of neurotransmitter
- Permeability of postsynaptic membrane altered
- Ion channels open
- Neurotransmitter binds to receptor on chemically gated channel
2, 1, 5, 4, 3
What is the normal direction of movement of an action potential along part of a neuron?
Dendrites to cell body
The nodes of Ranvier are:
Breaks in the Myelin covering
What characteristic is relevant to the endocrine system, rather than the nervous system?
Signalling may target many diverse cells
Which of the following is not part of the Peripheral Nervous System? A) Motor neurons B) Sympathetic Nervous System C) Spinal cord D) Afferent division E) Autonomic Nervous System
C) Spinal cord
Afferent Neurons:
Transmit messages to the spinal cord
Which of the following is not accomplished by the cerebral cortex?
A) Voluntary initiation of movement B) Control of breathing, circulation and digestion C) Final sensory perception D) Language ability E) Personality traits
B) Control of breathing, circulation and digestion
Which of the following does not participate in control of skeletal muscle activity?
A) Limbic system B) Cerebellum C) Supplementary motor area D) Premotor cortex E) Posterior parietal cortex
A) Limbic System
Which of the following functions is not associated with the hypothalamus?
A) Control of respiration and circulatory function
B) Control of thirst and urine output
C) Control of body temperature
D) Control of food intake
E) Extensive involvement with behavioural patterns
A) Control of respiration and circulatory function
Which of the following statements concerning the brain stem is incorrect?
A) The medulla is part of the brain stem
B) The brain stem is a critical connecting link through which all fibres traversing between the periphery and higher brain centres must pass
C) The brain stem controls sociosexual behaviours conducive to mating
D) The brain stem contains centres that control respiration, blood vessel and heart function, and digestive activities
C) The brain stem controls sociosexual behaviours conducive to mating
Information travels up the spinal cord to the brain via:
Ascending tracts
Receptors:
Four answers
- Respond to various physical or chemical changes in their environment
- Change other forms of energy into electrical energy
- Respond more readily to their adequate stimulus
- Are found at the peripheral endings of afferent neurons
Select the incorrect association: A) Chemoreceptor/oxygen concentration B) Mechanoreceptor/skeletal muscle stretch C) Nociceptor/solute concentration D) Photoreceptor/light E) Thermoreceptor/heat and cold
C) Nociceptor/solute concentration
