Neurobiology and Neuropharmacology Flashcards
State and describe the two different types of terminal nerve endings
Free (Non-encapsulated) Afferent Endings
-most common
-found in all epithelial cells, muscle, connective tissue, serous membranes (lining of peritoneal, pleural, and pericardial cavities)
Encapsulated Afferent Nerve Endings
a) Krause corpuscle (End Bulb)
-simplest type; axon terminates in oval bulb (lips, cheeks, nasal cavities, tongue, tendons, ligaments, membranes in joints, penis, clitoris)
b) Meissner corpuscle
-detect complex tactile stimuli (finger tips, palm of hands, soles of feet)
c) Pacinian corpuscle
-detect deep heavy pressure (deeper tissues of the hand and foot, pancreas, nipple, urethra, penis, clitoris)
d) Muscle Spindles
-regulate reflex action and muscle tone
-detect position and movement
-used by CNS to relay precise motor control
Compare the effects of the parasympathetic and the sympathetic
PARASYMPATHETIC
Heart - slows as body relaxes, less blood flow needed
Salivary Glands - stimulated as food can be eaten in a non-stressful situation
Iris of eye - circular muscle fibres contract, pupil constricts to protect retina
SYMPATHETIC
Heart - rate speeds up, more blood being pumped
Salivary Glands - inhibited, feeding not main priority
Iris of the eye - radial muscle fibres contract, pupils dilate
Define ganglions.
cluster of nerve cell bodies outside the CNS
What is grey matter?
nerves that lack a myelin sheath and neurilemma; do not regenerate
What is white matter?
nerves that contain myelinated fibres; capable of regeneration after damage
Function of an Axon
Transmits impulses away from cell body to other neurons or effectors
Function of a Dendrite
Transmits impulses towards cell body from a sensory receptor or from another neuron
Describe the Myelin Sheath
Fatty protein layer insulting the axon; prevents loss of charged ions from nerve cells
Describe the Neurilemma
Thin membrane surrounding the axon; promotes regeneration of damaged axons
What is a Node of Ranvier
- areas between sections of myelin sheath
- nerve impulses jump from node to node (saltorial conduction)
- rate of conduction greatest in small myelinated axons
Oligodendrocytes and Schwaan cells
Produce myelin
- oligodendrocytes CNS
- Schwaan PNS
Function of cerebellum
The part of the brain below the back of the cerebrum. I It regulates balance, posture, movement, and muscle coordination
Name the stages in the passage of a nerve impulse
(Action potential = +40mV)
“All or northing” - an action potential in one part causes another to develop in other parts of the neuron
1) Resting potential
- (-70)mV
-membrane is polarized (+ outside/- inside)
2) Stimulus reaches threshold potential. The potential rises above threshold, causing voltage gated channels to open
3) Depolarization
-less negative
-upward spike from -70mV
-caused by electrical disturbance
-Na+ channels open, Na+ diffuses into cell
-K+ channels closed
-positive inside, negative outisde
5) Repolarization
-moving back to resting potential
-downward spike to below -70mV
-K+ channels open, K+ diffuses out of neuron
-Na+ and k+ pump operates
-this reestablishes the resting membrane potential (+ve outside/-ve on inside)
6. Undershoot
-K+ channels closes slowly
-conc. gradients restored by active transport; resting potential restored
What are the 3 regions of the brain
- Forebrain (5 divisions)
- Midbrain (4 spheres)
- Hindbrain (3 divisions)
What are the 5 divisions of the forebrain
- Olfactory Lobes
- Cerebrum
- Frontal Lobe
- Parietal Lobe
- Temporal Lobe
- Occipital Lobe - Corpus Callosum
- Thalamus
- Hypothalamus
What are the 3 divisions of the hindbrain
- Cerebellum
- Pons
- Medulla Oblongata
Function of corpus callosum
Large bundle of nerve fibres that connect left and right cerebral hemispheres. In the lateral section, it looks a bit like a “C” on its side (part that if you cut through person becomes vegetable, use to do perform this procedure on serial killers)
Frontal lobe of cerebrum function
Used for reasoning, emotions, judgement, voluntary movements
Medulla Oblongata function
Lowest section of the brainstem (at top of spinal cord); controls automatic functions such as heartbeat and breathing
Occipital lobe of cerebrum function
Contains centres of vision and reading ability (located at back of head)
Parietal lobe of cerebrum function
Middle lobe; contains important sensory centres (touch and temp awareness), emotions and speech
Pons function
The part of the brainstem that joins the hemispheres of the cerebellum (located just above the cerebellum). Acts as a bridge between medulla and cerebellum to send messages.
Temporal lobe of cerebrum function
Contains centres of hearing and memory
What disease is characterized by decreased levels of dopamine? What about acetylcholine?
Parkinson’s and Alzheimer’s, respectively
