Lecture 1 Flashcards
What is physiology?
The study of how the body works.
What does the nervous system enable?
Rapid and flexible response to changes in external and internal environments of the body.
3 functions of the nervous system? (with brief description).
Sensory (senses internal and external changes),
Integrative (analyses and stores sensory info. making decisions on appropriate voluntary and involuntary responses),
Motor (initiates muscular activity or glandular secretions).
concentration of nerve cells per 1cm^3 of brain?
50 million.
What are the 3 types of neurons?
Sensory neurons, interneurons, motor neurons.
What inhibits flexor muscles from contracting during the knee-jerk reflex?
Interneurons.
2 divisions of the nervous system?
What parts do they involve?
Central nervous system (brain and spinal cord),
Peripheral nervous system (cranial and spinal nerves).
What 5 functions does the CNS control?
Integrates sensory information, Generates thoughts and emotions, Stores memory, Makes decisions, Initiates motor activity.
What 2 functions does the PNS control? And where do the instructions from both arise from?
Carry nerve impulses to and from CNS.
Connect CNS to sensory receptors, muscles and glands.
Arises from brain and spinal cord.
Do neurons divide?
No.
Do (neuro)glia have one function? Can they divide?
No, many. Yes (e.g. forming glial scars in brain disease).
How many neurons and glial cells does the brain contain?
10^11 neurons, 10^12 glial cells. Both contribute equally to brain weight.
3 parts of a neurone?
Cell body (soma/perikaryon),
Dendrites,
Axon.
Are dendrites and axons myelinated?
Dendrites aren’t, axons usually are.
Where do axons propagate nerve impulses to, and where do they terminate?
Propagate to another neuron, muscle fibre, gland.
Terminate at axon terminals/synapses.
What myelinates axons?
Oligodendrocytes in CNS, Schwann cells in PNS.
What does the cell body of neurons contain?
Normal cell organelles.
The perikaryon is the site of protein synthesis and degradation. What’s significant about a certain organelle that helps it accomplish this?
It’s rough ER is enlarged. Made up of Nissl substance.
How does structure differ between dendrites and axons?
Dendrites: Short, bristle-like, highly branched.
Axons: long, thin.
What receives nerve impulses?
Dendrites.
What are the 3 types of neurons by function?
Sensory neurons, interneurons, motor neurons.
What unique features do neuronal organelles present?
Very long axons, so nerve terminals remote from cell body.
Materials transported from between cell body and axons (orthograde/anterograde and retrograde transport).
Well defined cytoskeleton with special neurofilament.
4 components of neuronal cytoskeleton?
Actin microfilaments, microtubules, neurofilaments, tau.
How does Tau contribute to Alzheimer’s?
Accumulates in nerve cells in the brain, as neurofibrillary tangles.
