Ch 8

Question 1

Central Nervous System

Answer 1

spinal cord an brain

• receives input from sensory neurons –> motor neurons that innervate muscles/glands
• association neurons: integrate sensory info and help direct responses to maintain homeostasis/respond to the environment

Question 2

Gray Matter

Answer 2

• unmyelinated nerve cell bodies (clusters = nuclei)
• dendrites
• axon terminals

Question 3

White Matter

Answer 3

• myelinated axons
• -> tracts
• contains very few cell bodies

Question 4

What are clusters of cell bodies in CNS called?

Answer 4

nuclei

Question 5

What are tracts?

Answer 5

axon bundles connecting CNS regions

Question 6

Brain

Answer 6

• gray matter forms the cortex + deep nuclei
• white matter is deep forming tracts
• adult brain: 100 billion neurons
• receives 15% of total body blood flow
• -> cerebrum, diencephalon, midbrain, hindbrain

Question 7

Choroid Plexuses

Answer 7

consists of simple cuboidal to columnar epithelium in close association w/blood capillaries

• projects into the roofs of the ventricles (where fluid is)
• secrete CSF into ventricles and central canal of the cord

Question 8

CSF

Answer 8

secreted from choroid plexuses

• ->made from blood and returned to blood
• not part of circulation
• composition is different than blood
• turned over rapidly

Question 9

Cerebrum

Answer 9

• largest portion of the brain (80% of mass)
• responsible for higher mental functions
• consists of right/left cerebral hemisphere –> connected by corpus callosum

Question 10

Cerebral Cortex

Answer 10

• outer region: composed of gray matter w/underlying white matter
• gyri + sulci = convolutions
• each hemisphere is divided into 5 lobes (frontal, parietal, temporal, occipital, insula)

Question 11

Frontal/Parietal Lobes

Answer 11

-separated by central sulcus

1. pre central gyrus:
   - on frontal lobe
   - motor control
   - neurons called upper motor neurons
2. post central gyrus:
   - on parietal lobe
   - somatesthetic sensation (where we are in space)
   - ->called somatosensory cortex

Question 12

Temporal Lobe

Answer 12

auditory centers

Question 13

Occipital Lobe

Answer 13

vision and coordination of eye movements

Question 14

Insula

Answer 14

encoding of memory and integration of sensory info w/visceral responses
-receives olfactory, gustatory, auditory, and pain info

Question 15

Cerebral Lateralization

Answer 15

• each side of pre central gyrus controls movements on the contralateral (opposite) side of body
• somatesthetic sensation from each side of body projects to contralateral sides of post central gyrus
• communcaiton between the sides occurs through the corpus callous

Question 16

Corpus Callosum: right hemisphere

Answer 16

controls visuospatial tasks, recognizing faces, composing music

Question 17

Corpus Callosum: left hemisphere

Answer 17

controls language, speech, writing, calculations

Question 18

Limbic System

Answer 18

-group of brain regions responsible for emotional drives

Question 19

What are the areas of cerebrum?

Answer 19

cingulate gyrus
amygdala
hippocampus
septal nuclei
anterior insula
--> hypothalamus and thalamus (in the diencephalon) are part of the system

Question 20

What emotions are controlled by the limbic system?

Answer 20

Aggression: areas of amygdala and hypothalamus

Fear: amygdala and hypothalamus

Hunger/satiety: hypothalamus

Sex Drive: whole system

Goal-directed behaviors: hypothalamus and other regions

Question 21

Diencephalon

Answer 21

• part of forebrain
• includes: epithalamus, thalamus, hypothalamus, part of pituitary gland, and third ventricle
• surrounded by cerebral hemispheres
• regulates glands/hormones

Question 22

Hypothalamus

Answer 22

*important for maintaining homeostasis and regulated autonomic system

Question 23

Hypothalamus contains centers for…

Answer 23

LOTS of functions

• hunger/satiety and thirst
• regulation of body temp, sleep, and wakefulness
• sexual arousal and performance
• emotions of fear, anger, pain, and pleasure
• control of endocrine system
• controls hormone secretion from the pituitary gland

Question 24

Regulation of Pituitary Gland

Answer 24

1. ADH: regulated urine concentration
2. Oxytocin: important in reproduction
   - -> transported along hypothalami-hypophyseal tract to posterior pituitary gland (extension of neural tissue), where stored until needed
   - hypothalamus produces releasing hormones and inhibiting hormones that are transported to the anterior pituitary via circulation to regulate secretion of pituitary hormones

Question 25

Hindbrain

Answer 25

- composed of mesencephalon (pons and cerebellum) and myelencephalon (medulla oblongata) - -> ons houses sensory/motor tracts heading from/to the spinal cord and respiratory centers

Question 26

Cerebellum

Answer 26

- 2nd largest brain structure: gray matter outside, white matter inside - receives input from proprioceptors which sense joint angle, muscle length, and tension - works w/basal nuclei and motor cortex to coordinate movement - needed for motor learning and proper timing and force required to move limbs in specific task

Question 27

Myelencephalon

Answer 27

- made up of the medulla oblongata - all ascending/descending tracts between brain and spinal cord pass through medulla - contains nuclei required for regulation of breathing and CV response = vital centers 1. Vasomotor control: controls blood vessel diameter 2. Cardiac control center: controls HR 3. Respiratory center: works w/areas in the pons to control breathing

Question 28

Spinal Cord

Answer 28

-composed of white matter surrounding a gray matter core - gray matter is arranged with left/right dorsal horn and left/right ventral horn - -> dorsal root carries sensory info, ventral root is where motor info is exiting to muscles/glands -white matter composed of ascending/descending fiber tracts

Question 29

Ascending Tracts

Answer 29

convey sensory info from receptors in skin, muscles, joins, and organs -crossover of tracts (decussation) may occur in spinal cord or in medulla = contralateral

Question 30

Descending Tracts

Answer 30

Two groups 1. Corticospinal/Pyramidal: descend directly w/o synaptic interruption from cerebral cortex to the spinal cord (no synapse) 2. Extrapyramidal tracts: originate in ain stem and are controlled by motor circuits of the corpus striatum, substantial nigra, and thalamus

Question 31

Cranial Nerves

Answer 31

- part of PNS - nerves that arise directly from nuclei in brain - 12 pairs - most are mixed nerves - -> associated with vision, olfaction, and hearing are sensory only and have their cell bodies in ganglia located near the sensory organ