Integration of Physiological Systems Flashcards
What does the frontal lobe control?
What does the parietal lobe control?
What does the temporal lobe control?
What does the occipital lobe control?
What does the cerebellum control?
Decisions, emotion, speech, planning, motor control.
Sensory information
Hearing, facial recognition, memory
Visual information
Simple coordination, balance
Describe the features of the primary motor cortex.
Has a somatotopic map
Initiates movement
Requires the least electrical stimulation to work
Describe the features of the premotor area.
Split into dorsal and ventral: dorsal has full somatotopic map, ventral has no leg region on its map
Initiates controlled movement, acts through primary cortex
Requires more electrical stimulation than primary to work
Describe the features of the supplementary motor cortex (SMA).
Split into SMA proper and preSMA
Proper has map, linked to all others, requires greater voltage
Pre doesn’t initiate movement, not connected to other motor cortextes, involved in planning complex movement
Describe the features of the cingulate motor areas.
Three types: dorsal, ventra and rostral, all have somatotopic maps
Connected to all other motor areas
Involved in anticipation of movement
What are the differences between a receptor potential and an action potential?
RP is graded whereas an AP is not, RP can be hyperpolarising or depolarising whereas action potentials always lead to depolarisation of the membrane
RP tapers out, AP frequency reduces
How do Meissner and pacinian corpuscles respond to different forms of physical contact?
How do Ruffini corpuscles and Merkel discs respond to different forms of physical contact?
Adapt rapidly to stroking and vibration
Adapt slowly to stretch of skin and steady pressure/ texture
What tells you about the intensity of a sensory stimulus?
The frequency of nerve impulses
What are the functions of these brain structures:
- Cerebellum
- Thalamus
- Brainstem
- Basalganglia
Coordinate movement, equilibrium
Major sensory relay and intergration centre
Basal, crucial for deeply programmed functions
Control and refine movement
What area of the brain did patients studied by Broca and Wernick have damage to?
What did they find?
Broca - damage to left posterior inferior frontal gyrus, these patients couldn’t’ speak
Wernicke - left posterior section of the superior temporal gyrus, these patients couldn’t understand speech
What is the corpus callosum?
A wide flat bundle of largely myelinated nerve fibres which allow the brain hemispheres to communicate. Enables the brain to coordinate sensory and motor impulses
What are the ligands for gustatory receptors?
Sour: taste of acids, detection of protons (H+)
Salty: Na+
Umami: glutamate, nucleotides
Sweet and bitter: more complex larger molecules, various organic molecules
What type of cells are taste buds?
Epithelial or glial
Describe each of these taste bud cell types (i.e. what taste they perceive, their form etc.):
- glial like cells
- receptor cells
- presynaptic cells
Glial like cells - most abundant, responsible for perceiving salt, enclose the other cells in thin lamellae, glial cells don’t form synapses
Receptor cells - receptors for sweet, bitter or umami, don’t form synapses
Presynaptic cells - express ion channel for sour taste, behave like a typical receptor, form synapses with primary gustatory neurones
What is decussation?
Do taste signals do it?
Crossing over to opposite brain signals
No
How does olfactory transduction occur?
Only one basic signalling system, odorants bind to specific G-protein coupled receptors with cAMP as a second messenger. Each receptor has a specific receptor protein. The outside region is hypervariable the insides are identical and interact with the signalling system
How does odorant perception occur?
Receptors have different ranges, odorants activate different combinations of receptors, odorants bind to G-protein membrane protein which activates a cascade that depolarises the cell
What is the range of human hearing?
In what range is human hearing most sensitive?
Above what amplitude does sound cause damage to hearing?
What amplitude is conversation at?
20 - 20,000Hz
1000 - 3000Hz
80dB
~60dB
What do theses areas of the human ear do?
- outer ear
- eardrum
- middle ear cavity
Outer ear (pinna) - amplifies and directs sound
Eardrum (tympanic membrane) - vibrates with external sound
Middle ear cavity - filled with air contains
- malleus (hammer)
- incus (anvil)
- stapes (stirrup)
Which amplify movement of eardrum into oval window
Inner ear (cochlea) filled with endolymph which vibrates with the movement of the oval window so sound can be detected by sensory receptors
How does the attenuation reflex work?
Loud sounds make two muscles (tensor tympani muscle and stapedius muscle) contract making the chain of ossicles more rigid and diminishing sound conduction
What does the auditory (eustachian tube) do?
Exposes the middle ear to atmospheric pressure by connecting it to the pharynx, normally closed but opens during yawning, swallowing or sneezing
What transmitter do ear hair cells use?
Glutamate
Describe these types of hearing loss and their causes:
- conductive
- sensorineural
- central
Damage to external or middle ear, ear clogged with wax, damage to tympanic membrane, fluid in middle ear, disease/ trauma to malleus
Damage to inner ear structures, treat with implants, excessive noise damages hair cells, they are also lost with age
Damage to neural pathways or auditory cortex, uncommon cause
What does the vestibular system do?
What do the macula do?
What do the crista do?
Detects change in motion and head position, located in the inner ear, has two receptors macula and crista
Perceive gravity using calcium carbonate crystals
Perceive acceleration/ deceleration of movement, movement shifts the jelly like cupula and triggers a response in hair cells in the crista
What is the range for visible light?
400 - 750nm
What is the cornea?
Transparent layer that protects the eye, involved in focusing and refracting light
What is the iris/ pupil?
A muscle that constricts and relaxes to regulate the diameter of the pupil. The pupil shrinks/ expands to match changing light conditions
What is the lens?
A transparent tissue, made of tightly packed crystallin proteins, attached to the ciliary muscle and enables fine focusing of light
What is the aqueous humour, where is it found?
What is the vitreous humour, where is it found?
Low protein plasma like fluid found in the front eye chamber
Clear gelatinous substance, keeps the retina in place, found in the main eye chamber
Does the eye use a concave or convex lens?
Convex
What is the retina?
Covers the inside of the eyeball, contains cells sensitive to light
Describe rods and cones.
Rods - most common (in mammals), sensitive to light so can work at low light intensities
Cones - three types, red blue and green
What happens when 11-cis-retinal is hit by light?
It photoisomersises to the all trans retinal form which no longer fits in the opsin protein. Causing the protein to change conformation triggering a phototransduction cascade in the photoreceptor cell
Describe the phototransduction cascade.
Photon hits causing 11-cis-retinal to be converted to all trans form
Causes a conformation change which activates transducin
Transducin activates a cGMP phosphodiesterase
This breaks down cCGP
A reduction in cGMP causes cGMP sensitive ion channels to close hyperpolarising the photoreceptors membrane
How to photoreceptors respond to stimulation?
They hyperopolarise