Central Nervous System

Question 1

Regions + organizations of CNS

Answer 1

Adult brain regions
1. Cerebral hemispheres: cortex, cerebral white matter, basal ganglia
2. Diencephalon: Thalamus, hypothalamus, epithalamus
3. Brain stem: midbrain, pons, medulla
4. Cerebellum

Spinal Cord

Question 2

Ventricles of brain

Answer 2

• connected to one another and to central canal of spinal cord
• lined by ependymal cells
• contain cerebrospinal fluid
• 2 c-shaed lateral ventricles
• third (line in middle) + fourth ventricles (diamond shape)

Question 3

Hydrocephalus

Answer 3

Build up of CSF in the brain leading to enlargement of brain vesicles and that leads to high pressure and headaches.

Question 4

Cerebral hemispheres + 5 lobes

Answer 4

Surface markings
- ridges (gyri)
- shallow grooves (sulci)
- deep grooves (fissures)

5 lobes per hemisphere
- frontal
- parietal
- occipital
- temporal
- insula

Question 5

Cerebral cortex + 3 functional areas

Answer 5

• site of conscious mind: awareness, sensory perception, voluntary motor initiation, communication, memory storage, understanding

3 types of functional areas:
- motor area: control voluntary movement
- sensory area: conscious awareness of sensation
- association areas: integrate diverse info

Question 6

Motor areas

Answer 6

1. Primary somatic motor cortex
   - control of skeletal muscles
   - pyramidal cells –> pyramidal tracts
2. premotor cortex
   - plans movements, coordinates mov’ts of several groups into complex tasks (musical instrument)
3. Broca’s area
   - motor speech area (left hemisphere)

Question 7

Sensory Areas

Answer 7

• primary somatosensory cortex: parietal lobe + touch
• association areas: understanding of sense
• visual areas
• auditory areas
• olfactory area - smell
• visceral sensory area - full bladder
• vestibular cortex - equilibrium

Question 8

Visual areas

Answer 8

Occipital lobe
1. primary visual striate cortex
- extreme posterior tip of occipital lobe
- receives visual info from retinas

2. visual association area
   - uses past visual experiences to interpret visual stimuli (color, form, movement)
   - recognizes faces + familiar objects

Question 9

Auditory areas

Answer 9

Temporal lobe
1. primary auditory cortex
- temporal lobes
- interprets info from inner ear as pitch, loudness, and location

2. Auditory association area
   - stores memories of sounds and permits perception of sounds (car brakes, voices)

Question 10

Prefrontal cortex

Answer 10

Frontal lobe
- most complicated region
- intellect, cognition, recall, personality
- working memory for judgement, reasoning, conscience
- develops slowly in children and depends on feedback from environment socially
- lesions here will cause changes in personality

Question 11

Lateralization of cortical function

Answer 11

Lateralization: division of labor bw hemispheres
- left hemisphere: controls language, math, logic
- right hemisphere: insight, visual spatial skills, intuition, artistic skills
- left + right communicate via fiber tracts in cerebral white matter

Question 12

Cerebral white matter

Answer 12

• myelinated fibers + their tracts
• responsible for communication
• commissures: connects 2 hemispheres (corpus callosum)
• association fibers: connect diff parts of same hemisphere
• projection fibers: connect hemispheres w/ lower brain/spinal cord

Question 13

Basal Nuclei Ganglia

Answer 13

Subcortical nuclei
- help regulate attention + cognition
- regulates intensity of slow/stereotypes movements
- inhibit unnecessary movements
- disorders here cause too much movement like huntingtons disease or too little movement like parkinsons

Question 14

Diencephalon

Answer 14

3 paired structures
1. thalamus: relay station
2. hypothalamus: homeostasis
3. epithalamus: melatonin

Question 15

Thalamic function

Answer 15

• gateway to cerebral cortex (relay station)
  sorts, edits, and relays info (afferent impulses from all senses)
• thalamus = inner room

Question 16

Hypothalamic function

Answer 16

• Autonomic control center: blood pressure, rate and force of heartbeat, digestive tract motility
• Emotional response (limbic system): perception of pleasure, fear, and rage in biological rhythms and drives
• Fearful person: pounding heart, high blood pressure, sweating, dry mouth
• Also regulated body temp, food intake, water balance, thirst
• connected to pituitary gland

Question 17

Epithalamus

Answer 17

Part of diencephalon
- pineal gland: secretes melatonin which helps regulate sleep-wake cycles

Question 18

Brain stem

Answer 18

3 regions
1. Midbrain: substantia nigra (parkinsons disease
- Functionally linked to basal ganglia
- produces neurotransmitter dopamine
- degeneration of these dopamine releasing neurons case parkinsons

2. Medulla oblongata: connects to spinal cord
   - autonomic reflex centers - unconscious activity

cardiovascular center
- cardiac center = adjusts force + rate of heart contractions
- vasomotor center = adjust blood vessel diameter

Respiratory centers
- generate respiratory rhythm
- control rate + depth of breathing

damage to brain stem, esp medulla will lead to death

3. Pons: bridge

Question 19

Cerebellum

Answer 19

• dorsal to brainstem, inferior to occipital lobe
• subconsciously provides precise timing and patterns of skeletal muscle contraction
• tests: balance, coordination, finger-nose
• learning motor tasks (sports/musical instruments)

Question 20

Functional Brain systems

Answer 20

Networks of neurons that work together and span wide areas of the brain

limbic system: emotional brain
- hippocampus, amygdala, cingulate gyrus, hypothalamus

reticular formation: wakefulness

Question 21

Limbic system

Answer 21

Emotional/affective brain
- amygdala: recognizes angry/fearful facial expressions, assesses danger, and elicits the fear response, BODY ALARM SYSTEM
- cingulate gyrus: plays a role in expressing emotions via gestures, mental conflict
- limbic + olfactory connected
- odors recall memories

Question 22

Emotion + cognition

Answer 22

Limbic system (emotional brain) interacts w/ prefrontal lobes (thinking brain)
- our emotions sometimes override logic and why reason cant stop us from expressing emotions
- hippocampus + amygdala –> play a role in memory

Question 23

Reticular formation

Answer 23

RAS (reticular activating system)
- sends impulses to the cerebral cortex to keep it conscious and alert
- filters out repetitive and weak stimuli and lets important ones in
- RAS inhibited by sleep centers
- severe injury results in coma

Question 24

Sleep

Answer 24

• state of partial unconsciousness from which a person can be aroused by stimulation
• environmental monitoring continues (can be aroused –> crying baby; sleepwalkers avoid obstacles
• 2 major sleep types defined by EEG patterns
  1. nonrapid eye movement NREM
  2. Rapid eye movement REM

Question 25

Sleep importance

Answer 25

- slow wave sleep (NREM stages 3 + 4) is presumed to be restorative stage - people deprived of REM sleep become moody + depressed - sleep deprivation linked to increased heart disease, DM, kidney disease, stroke, HBP - REM sleep may be a reverse learning process where superfluous info is purged from the brain - daily sleep requirements decline w/ age

Question 26

Language

Answer 26

Langauge implementation system - basal nuclei - Broca's area (frontal lobe): expressive speech - wernickes area (temporal lobe): understanding speech Corresponding areas on right side are involved w/ nonverbal language components

Question 27

Memory

Answer 27

encoding, storage, retrieval of info 2 stages of storage - short term memory: working memory, temporary holding of info, limited to 7/8 pieces of info (telephone #) - Long term memory: LTM has limitless capacity

Question 28

STM --> LTM

Answer 28

Factors affecting transfer from STM to LTM - emotional state: best if alert, motivated, surprised, and aroused (norepinephrine) (teachers/emotional situation) - rehearsal: repetition + practice - association: tying new info w/ old memories - automatic memory subconscious info stored in LTM

Question 29

Protection of brain

Answer 29

- bone (skull) - membranes (meninges) - water cushion (cerebrospinal fluid) - blood-brain barrier (filters toxins, but not lipid soluble like alcohol)

Question 30

Meninges

Answer 30

Cover + protects CNS 3 layers - Dura mater: tough mother, fibrous CT - arachnoid mater: spider, subarachnoid contains CSF + blood vessels - pia mater: gentle mother, delicate CT, clings to brain like saran wrap Meningitis: viral/bacterial inflammation

Question 31

Cerebrospinal fluid CSF

Answer 31

Functions - gives buoyancy to CNS organs and floats the brain - protects CNS from blows + other traumas - nourishes brain and carries chemical signals - constant volume, replaced every 8 hours - choroid plexus: hangs from roof of ventricles, produces CSF

Question 32

Spinal cord

Answer 32

Location - begins at foramen magnum - ends as conus medullaris at L1 vertebra Functions - provides 2 way communication to and from the brain - contains spinal reflex centers Protected by vertebral column, meninges, cerebrospinal fluid in subarachnoid space

Question 33

Gray Matter

Answer 33

- Dorsal horns: somatic + visceral sensory - ventral horns: somatic motor neurons whose axons exit the cord via ventral roots - Lateral horns (only in thoracic and lumbar regions): sympathetic neurons - Dorsal root (spinal) ganglia: contain cell bodies of sensory neurons

Question 34

Spinal cord trauma

Answer 34

Transection (cut): results in total motor and sensory loss in regions inferior to the damage - Quadriplegia: transection in cervical region - Paraplegia: transection bw T1 + L1