Physiology Review Flashcards
What composes the Central Nervous System [CNS]?
The brain and spinal cord
What composes the Peripheral Nervous System [PNS]?
Nerves! SPINAL nerves (carry impulses to and from the spinal cord) and CRANIAL nerves (carry impulses to and from brain)
The PNS has two principle subdivisions of FUNCTIONAL classification. What are they?
- Sensory (AFFERENT) division
2. Motor (EFFERENT) division
Briefly summarize the sensory (AFFERENT) division of the PNS
Info TO the CNS!
- Informs the CNS of what’s going on with the body (kind of like the private investigators of the body, constantly gathering info to report to the CNS boss)
- somatic sensory fibres (somatic afferents) deliver impulses from the BODY (skin, skeletal muscles and joints)
- visceral sensory fibres (visceral afferents) transmit impulses from visceral ORGANS
Briefly summarize the motor (EFFERENT) division of the PNS
Info FROM the CNS to effector organs, muscles and glands; has 2 subdivisions:
- Somatic Nervous System (voluntary!)
- Autonomic Nervous System (involuntary!) **
PNS > Motor (EFFERENT) division > Autonomic Nervous System [ANS] > ??
What are the two parts of the ANS?
- Sympathetic Nervous System
2. Parasympathetic Nervous System
What does the Sympathetic Nervous System do? [SNS*]
“Fight or flight”
- Stimulated when emotionally OR physically stressed
- Increased HR, RR, BP, and blood glucose; dilated pupils; cold and sweaty skin
- blood TO heart, lungs and skeletal muscles, AWAY from digestive
- E = exercise, excitement, emergency, embarrassment
What does the Parasympathetic Nervous System do? [PaNS*]
“Rest and digest”
- promotes digestion, elimination and conservation of energy
- Decreased HR, RR, BP and glucose; constricted pupils; warm skin
- D = digestion, defecation, diuresis
What are the two types of PaNS receptors and how many of each are there?
Nicotinic (2 types)
Muscarinic (5 types)
Neurons communicate with other cells (other neurons, muscle cells, or cells in secretory gland) in order to transmit a signal from the CNS to bring about an action or response from the body.
What are the two basic steps of this process?
- Axonal conduction
2. Synaptic transmission
Neurons communicate with other cells (other neurons, muscle cells, or cells in secretory gland) in order to transmit a signal from the CNS to bring about an action or response from the body.
Describe axonal conduction.
Axonal conduction:
- process of conducting the action potential down the axon of the neuron.
** the axon is the communicator branch of the neuron**
Neurons communicate with other cells (other neurons, muscle cells, or cells in secretory gland) in order to transmit a signal from the CNS to bring about an action or response from the body.
Describe synaptic transmission.
Synaptic transmission:
- the process by which info (via neurochemicals?) travels across the gap between the neuron to the post-synaptic cell.
- requires neurotransmitter molecules that must bind to receptors on the post-synaptic cell. What the post-synaptic cell does about it depends on the type of neurotransmitter, and also what type of cell it is itself.
True or False?
Since there are two steps involved in neuronal activities (axonal conduction and synaptic transmission), neuropharmacologic agents act on altering either one of these. Most of these drugs target axonal conduction.
FALSE
Most neuro. drugs act by altering synaptic transmission because effects can be more SELECTIVE as opposed to drugs altering axonal conduction.
Since there are two steps involved in neuronal activities (axonal conduction and synaptic transmission), neuropharmacologic agents act on altering either one of these
What are some properties of axonal conduction drugs?
- not very selective –> indications are limited
- ie. local anaesthetics inhibit/decrease axonal conduction within the nerves it can reach
Since there are two steps involved in neuronal activities (axonal conduction and synaptic transmission), neuropharmacologic agents act on altering either one of these
What are some properties of drugs that alter synaptic transmission?
- highly selective –> have many uses
- this is because synapses at different sites employ different types of neurotransmitters. AND there are also different kinds of receptors for each transmitter, hence drugs can target a specific neurotransmitter or receptor and leave others unaffected.
