524- Nervous B CNS

Question 1

What nervous system organs fit into the CNS and PNS?

Answer 1

⭐CNS: Spinal cord
: Brain

⭐PNS: Nerves
: Ganglia
: Receptors

Question 2

Functions of the CNS?

Answer 2

• integrate sensory information from receptors

- coordinate activity of effectors (conscious or unconscious)

Question 3

Functions of the PNS?

Answer 3

DETECT STIMULI and TRANSMIT action potentials between receptors, CNS and effectors.

Question 4

> Difference between grey and white matter

> What cells form the myelin sheath?

Answer 4

⭐ GREY (unmyelinated)

⭐ WHITE (myelinated axons).
myelin sheath formed by oligodendrocytes in CNS
Schwann cells in PNS

Question 5

What do you call the collections of neuron cell bodies and bundle axons in:

> CNS
PNS

Answer 5

⭐CNS: Nucleus, Tract

⭐PNS: Ganglion, Nerve

Question 6

Responsibilities of Brain and Spinal Cord?

Answer 6

⭐ Brain:

• manage sensory info + give orders
• thinking, feeling, remembering

⭐Spine:

• directs 2 way signals between brain and the rest of the body
• control basic muscle REFLEX that doesn’t need the brain to work.

Question 7

What are the 3 folds found in the brain called and for?

Answer 7

⭐ Gyri - (ridges/little creases) (gyrus=1)
⭐ Sulci - (shallower grooves) (sulcus=1)
⭐ Fissures - (deep grooves)

used as landmarks to identify parts of the brain.

Question 8

Why was the folds in the brain formed?

Answer 8

We need lots of synapses to be able to manage higher processes, which needs LOTS of nervous tissue. As the cerebrum grew through evolution to increase the surface area to hold these synapses, the skulls stayed the same, causing it to wrinkle and form these grooves to fit in.

Question 9

How are parts of the brain kept separate? (4)

Answer 9

⭐ transverse cerebral fissure : cerebrum/cerebellum

⭐ longitudinal fissure: L/R cerebral hemispheres

⭐lateral sulcus : parietal/temporal, temporal/frontal

⭐ central sulcus: frontal/parietal

Question 10

> Location and function of white matter.

> What is corpus callosum?

Answer 10

> INSIDE cerebral cortex
- they are tracts and fibers that transmit info between different parts of the brain.

⭐ thick band of white matter that allows communication between L & R hemispheres. They are formed by commissural fibers.

Question 11

What are the 3 fibres in the brain? (function)

Answer 11

connects:
⭐ Association fibres- parts in SAME hemisphere

⭐ Commissural fibres- similar areas in L & R cerebral hemisphere.

⭐ Projection fibres- cerebral cortex to lower parts of the brain

Question 12

What is the cerebral cortex? (made up of, what happens here?)

Answer 12

⭐ made up of wrinkled outer layer of grey matter
(where ALL CONSCIOUS processes occur)
- think, sense, feel, conscious control of mvmnt, facial expressions

⭐ and inner, squishy layer of white matter beneath it.

Question 13

Function of frontal lobe + what it cortex(s) forms it

Answer 13

“control of movement (motor skills) and memory”

⭐ Primary cortex -controls all skeletal muscles + facial expressions. in front of central sulcus

⭐Premotor cortex- planning of movement. sends instructions to primary cortex (to do it correctly)

⭐Broca’s Area- controls speech (mouth and larynx to make sound) + planning of speech

⭐Prefrontal cortex- concentration, impulse control, THINKING (solve problems)

Question 14

Functions of the Parietal lobe + what cortex (s) forms it

Answer 14

“sense of touch” (pain & pressure)

⭐Primary somatosensory cortex
- gets and interprets type & intensity of sensory input received by brain and proprioceptors (position receptors) + nociceptors (pain receptors) + mechanoreceptors (pressure, touch, vibration) from the skin

⭐Somatosensory association cortex
- using emotion and memory it adds meaning to sensory info

Question 15

Functions of the occipital lobe + cortex (s) forming it

Answer 15

“vision”

⭐Primary visual cortex- gets visual info from retinas

⭐Visual association area- using memory and emotions it adds meaning to the visual information

Question 16

Functions of the temporal lobe + cortex (s) forming it

Answer 16

“hearing”

⭐Primary auditory cortex
- gets sensory (hearing) info from inner ear (like pitch, loudness, location)

⭐Auditory association area
- using memory and emotion, adds meaning to sensory (hearing) to what’s been heard

⭐Wernicke’s Area
- for understanding language and speech (both written and spoken)

⭐Olfactory Cortex

• receives olfactory (smell) info from nasal cavity
• awareness of odors

: Olfactory bulb and tract send info from nasal cavity to brain about what you’ve smelt.

Question 17

Functions of the insula + cortex (s) forming it

Answer 17

“sense of taste”

⭐Gustatory cortex
- gets and interprets taste stimuli from mouth

Question 18

Function (2) and location of basal ganglia (what is it)

Answer 18

“collections of grey matter”

⭐deep within white matter, lateral to thalamus

⭐role is to act as relay stations between the cerebral cortex, cerebellum and brainstem

• start, stop and the control of movement

Question 19

Functions and location of diencephalon (what are the 3 things making it up)

Answer 19

[deep inside cerebral hemispheres and superior to brainstem]

> Thalamus: sensory relay station, directs all sensory info (except smell) through the thalamus to the correct parts of the cortex.

> Epithalamus: secretes melatonin which help regulate the sleep-wake cycle

> Hypothalamus

Question 20

What are the roles of the hypothalamus? (7)

Answer 20

1) autonomic control centre
2) emotional response centre
3) body temp regulation
4) regulation of food intake
5) regulation of water balance
6) regulation of sleep-wake cycle
7) control of hormone secretion

Question 21

What is the brainstem? (function, location)

Answer 21

“conduction pathway for neurons, carrying info between upper and lower areas of the nervous system”

• superior to inferior:

⭐Midbrain
⭐Pons
⭐Medulla oblongata

Question 22

Functions of the midbrain (3), pons (1) and medulla oblongata (4)

Answer 22

⭐Midbrain
: Visual reflex- head & eye tracking
: startle reflex - turn head toward unexpected sound
: part of conducting auditory signals (inner ear-> auditory cortex)⭐Pons
: control of RR and rhythm⭐Medulla oblongata
: control RR and rhythm
: regulation of BP (blood vessel diameter altered)
: HR and force of contraction
: reflexes like vomiting, hiccupping, swallowing, sneezing

Question 23

What is the reticular formation? (location, function)

Answer 23

“clusters of grey matter running throughout the entire brainstem”

⭐regulates and maintains levels of consciousness and alertness.

(when asleep, it can prompt a response towards sensations)

Question 24

What is the cerebellum? (location, function)

Answer 24

smaller part of the brain, inferior to the cerebellum containing both grey and white matter and also has 2 hemispheres. It has more neurons than the cerebrum.

⭐maintain balance
- involved in controlling planning, timing, and coordination of movements (like learning motor skills e.g., riding a bike)

Question 25

What is the limbic system?? (location, function)

What are the hippocampus and amygdala involved in?)

Answer 25

“emotional brain”

deep within medial aspect of cerebrum (hemispheres)

⭐helps regulate emotion and memory
- part of behavior, endocrine and autonomic activities

Hippocampus: involved in short term memory
Amygdala: control sexual and social behavior

Question 26

What are the ventricles? (4)

Answer 26

4 connected compressed fluid-filled spaces.

⭐lateral ventricle (C-shaped, in each hemisphere)
⭐Third ventricle (in diencephalon)
⭐cerebral aqueduct
⭐fourth ventricle (kite shaped, in brainstem)

Question 27

What are the meninges? (3…+1)

function, contains

Answer 27

3 connective tissue layers that cover and protect the brain + spinal cord + blood vessels. It contains cerebrospinal fluid.

⭐Dura mater: leathery, tough, 2 layered sheet of fibrous connective tissue.

⭐Arachnoid mater: loose brain covering that moves towards the pia mater (looks like webs)

⭐Pia mater: delicate connective tissue with lots of tiny blood vessels. (adhered tightly to brain)

-subarachnoid space: between arachnoid and pia mater, contains CSF.

Question 28

What is cerebrospinal fluid (“CSF”)?
(function)
(how does it distribute the CSF?)

Answer 28

filtered blood from choroid plexus (clusters of think walled capillaries found in ventricles).

> protects brain from blows and other trauma
- brain floats in this liquid cushion to prevent it from collapsing under its own weight.

> EPENDYMAL CELLS covering the choroid plexuses have CILIA that spread the CSF. (lateral ventricle>third ventricle>cerebral aqueduct>fourth ventricle>into subarachnoid space in brain + spinal cord>drains back into blood of dural sinus through arachnoid villi)

Question 29

What is the blood brain barrier? (why do we need it?)

Answer 29

A selective barrier against substances in the blood before they meet neurons, made up of the:

• capillary wall endothelium
• thick basal lamina (surrounds capillaries)
• astrocytes (clings to the capillaries)

This is because we need a CONSTANT internal environment for normal brain function.

Question 30

How does information/action potentials received from skin>spine> brain> and back out?

Answer 30

Sensory info from peripheral sensory receptors enters the spinal cord the sensory neurons in the dorsal root. These sensory neurons synapse with 2nd sensory neurons, travelling up the spinal cord through specific sensory tracts to the thalamus. A short neuron takes this info (from thalamus) to the cerebral cortex).

Motor neurons travel in different tracts down the spinal cord from the motor cortex. They synapse with the 2nd motor neuron which leaves the spinal cord through the ventral root and onto the effector organs.