Describe the route that sound is perceived.
- Hair cells on basilar membrane
- Information carried on cochlear branch of vestibulocochlear nerve (cranial nerve VIII).
- Cochlear nuclei of medulla oblongata
- Inferior colliculus
- Medial geniculate nucleus of the thalamus.
- Auditory cortex of the temporal lobe.
Describe the steps in maintaining equilibrium.
- Hair cells of the vestibule and semicircular ducts
- Vestibular branch of the vestibulocochlear nerve (VIII).
- Vestibular nuclei in medulla oblongata
- Superior colliculi detect automatic eye movements occurring in response to sensation of motion. Cranial nerves involved in eye, head, and neck movement. The vestibular nuclei relay information about position and balance to the cerebellum. Descending vestibulospinal tracts carry instructions to peripheral muscles.
Schwann cells
- cells that cover peripheral axons and play a role in axon repair after injury
- myelinating Schwann cells produce myelin, speed signal
satellite cells
- surround neuron cell bodies around PNS ganglia, regulating the environment around the neuron
- equivalent in CNS are called astrocytes
What happens to voltage gated ion channels at -70mV, -60mV and +30mV?
-70mV: channel closed; activation gate closed
-60mV: channel open; both gates open
+30mV: channel inactivated; inactivation gate closed
continuous vs. saltatory propagation
- continuous: AP moves along unmyelinated axon
- saltatory: AP jumps between nodes along myelinated axon
sensory (afferent) division
- part of PNS that sends info. from peripheral tissues in PNS to CNS
motor (efferent) division + SNS/ANS
- part of PNS that sends motor commands from CNS to peripheral tissues
- somatic nervous system (SNS): somatic efferent neurons; voluntary; conscious control of movement
- autonomic nervous system (ANS): visceral efferent neurons; involuntary; autonomic regulation of activities
fissures, gyri, and sulci
- parts of the cerebrum
- fissures: deep grooves subdividing each hemisphere
- gyri: folds (increase surface area)
- sulci: shallow grooves that separate adjacent gyri
cerebrum
- conscious thought
- memory (storage and processing)
- sensory processing
cerebellum
motor control
diencephalon
- connects cerebrum and CNS
- thalamus: relays + processes sensory info.
- hypothalamus: emotions, hormones, autonomic functions
brain stem
- midbrain: consciousness, auditory and visual processing
- pons: connects cerebellum to brainstem, somatic + visceral motor controls
- medulla oblongata: autonomic functions
frontal lobe
- learned movements
- intellectual functions
Broca’s area
- found in the frontal lobe
- speech production
parietal lobe
sensory info. processing
Wernicke’s area
- language comprehension
- integration of sensory info.
- coordinates access to visual and auditory memories
How is gravity and acceleration detected?
when head is tilted:
- gravity causes otoliths to shift
- hair cell processes distorted
- receptors stimulated
activation of rod cells
- in the dark, Na+ channels are open in presence of cGMP (retinal in 11-cis form)
- when light hits, rhodopsin switches 11-cis retinal to 11-trans, activating opsin
- opsin activates transducin, which activates PDE
- PDE breaks down cGMP and Na+ channels are inactivated
- less Na+ causes hyperpolarization and less neurotransmitter release, = decreased activity
What is the area with the highest concentration of photoreceptors?
the fovea (centre of macula)
What happens to the eye for close vision?
- ciliary muscles contract and pulls ciliary body towards centre
- lens made more spherical
What happens to the eye for distant vision
- ciliary muscles relax
- lens flatter in shape
