Chapter 14 The Brain and Cranial Nerves

Question 1

List 4 major brain regions

Answer 1

1. Cerebral hemispheres
   Includes the basal nuclei (ganglia)
2. Diencephalon
   Thalamus & hypothalamus
3. Brain stem
   Midbrain, pons, & medulla oblongata
4. Cerebellum

Question 2

List 4 lobes

Answer 2

Frontal, parietal, temporal, & occipital

Question 3

Cerebral Cortex has 3 functional areas:

Answer 3

1) sensory (taking info in)
2) motor (allow us to move)
3) association areas ( more integrative such as memeory, emotion, willpower, intelegence. Complex areas. Taking in sensory info, anazying it and figuring out the proper responce)

Question 4

Sensory Areas

Answer 4

• Located in the posterior half of the hemisphere
• Receive and interpret information from sensory receptors

Primary Somatosensory Area
•Located in the postcentral gyrus (parietal lobe)
•Receives input from skin sensory receptors for touch, pain, & temp.
•Receives input from muscle, tendon, & ligament •proprioceptors about body position & movements
•you have this info coming in, how do you know where its coming from? Neurons can idenfiy the body region its coming from. This is cause the poscentral gyus is divided into regions for each areas of the body
- Each region is represented by the number of receptors it has.
- Lots of touch receptors = bigger area on the map.
- Example the hands are huge since they posses a lot more touch receptors then feet or trunk which takes up less space.

Question 5

Motor Areas

Answer 5

• Control motor functions
• Located in the posterior part of the frontal lobe

Primary Motor Area
• Located in the precentral gyrus
• Controls voluntary contractions of specific skeletal muscles

Broca’s Speech Area
• Located close to lateral sulcus (usually in left hemisphere)
• Directs muscles of tongue, throat, & lips used in speech production
• damage can causes Non-fluent aphasia slow speech

Question 6

Association Areas

Answer 6

Widespread areas in all lobes

Somatosensory Association Area
• Lies posterior to & receives input from the primary somatosensory area
• Can analyze, recognize, & act on sensory input in relation to past experiences it stores

Premotor Area
• Lies anterior to & communicates with the primary motor cortex
• Controls learned motor activities involving complex sequential muscle contractions

Prefrontal Cortex
• Located in anterior frontal lobe
• Involved with intellect, complex learning abilities, recall, & personality
• A role in judgment & mood
• Involved in reasoning, planning for the future, & ‘conscience’

Language Areas
• Near lateral sulcus in left hemisphere
• Involved in recognition of spoken words & written language
• Interprets meaning of words & converts words to thoughts (Wernicke’s area)

Question 7

Basal Nuclei

Answer 7

• Are 3 masses of grey matter located deep within the cerebral hemispheres
• Inhibit antagonistic & unnecessary movements
• Regulate muscle tone

Question 8

Cerebral White Matter: There are 3 types of tracts:

Answer 8

1. Association tracts → axons connect gyri in same hemisphere
2. Commissural tracts → axons connect gyri in one hemisphere to corresponding gyri in the other hemisphere (e.g., corpus callosum
3. Projection tracts → axons run vertically to connect cerebrum to lower parts of brain & spinal cord (ex. Cerebral cortex connected to thalamus)

Question 9

Diencephalon

Answer 9

Thalamus
• Paired oval masses of about 7 groups of grey matter nuclei
• Acts as a major relay station to conduct sensory impulses to primary sensory areas of the cerebral cortex
• gateway to the cerebral cortex (almost evey sensry tract must go through the thalamis when sends the sensory info to the right area of the brain)

Hypothalamus
• Cluster of a dozen nuclei located below the thalamus
• Regulates the pituitary gland via hormones called releasing hormones & inhibiting hormones (Doesn this by releasing hormones and inhibiting hormones. Control center of the pituitary gland)
•Produces oxytocin (stimulate contraction of SM in uterus during birth) & antidiuretic hormone (stimulates water reabsorption in the kidneys, decreasing urine production)
•Regulates body temperature, water balance, & food intake

Question 10

Brain Stem: midbrain

Answer 10

All contain nuclei, sensory, & motor tracts

Midbrain
• Area b/t the diencephalon & pons
• Contains the cerebral aqueduct
• Coordinates movements of head, eye, & trunk in response to visual/auditory stimuli
• Startle reflex

Question 11

Brain Stem: Pons

Answer 11

• Bulge in brainstem above medulla
• Relays motor information from the cerebrum to the cerebellum
• Contains nuclei involved in respiration

Question 12

Brainstem: Medula Oblongata

Answer 12

• Continuous with the spinal cord
• A large motor tract forms bulges (pyramids) on anterior surface → crossover point
• Contains nuclei that control heart rate, blood pressure, & breathing rhythm

Question 13

Cerebellum

Answer 13

• Second largest part of brain
• Surface is highly convoluted
• Has 2 hemispheres connected by the vermis
• Grey matter is located in outer cortex (folia = slender folds) & in deeper nuclei
• White matter tracts are called arbor vitae
• Functions to smooth & coordinate skeletal muscle contractions
• Regulates posture & balance
• Damange to cerebellum leads in disruption in muscle cooridation/muscle tone, make a person clumsy and unsure while walking leading to staggering (this is what an incredibly drunk person looks like when trying to walk. Drinking alcohol actually impairs cerebellar function)