Behavior Flashcards Preview

MCAT Psychology > Behavior > Flashcards

Flashcards in Behavior Deck (27):
1

Central nervous system components

Brain and spinal cord

2

Peripheral nervous system divisions

Somatic and autonomic. Autonomic further broken down into sympathetic and parasympathetic

3

Describe a reflex arc

Sensory receptors detect pain > transmit signal up spinal cord through interneurons > interneurons send signals to muscles > muscles respond to reflex. By the time the brain receives the sensory info, the muscles have already responded

4

Lower motor neurons

- Efferent neurons of PNS; control skeletal muscle
- Efferent neurons in contact with other end of motor unit form neuromuscular junction
- Abnormalities cause weakness

5

Neuromuscular junction

Interface between lower motor neuron (PNS) and muscle

6

Lower motor neuron signs (LMN signs)

- Atrophy of skeletal muscle
- Fasciculations (involuntary twitches)
- Hypotonia (decrease in muscle tone; how much muscle is contracted when a person is relaxed)
- Hyporeflexia (decreased muscle stretch reflex)

7

Fasciculations (definition and cause)

- Involuntary twitches of skeletal muscle
- Caused by abnormalities in lower motor neurons (LMN sign)

8

Hypotonia (definition and cause)

- Decrease in muscle tone; how much muscle is contracted when a person is relaxed
- Caused by abnormalities in lower motor neurons (LMN sign)

9

Hyporeflexia (definition and cause)

- Decreased muscle stretch reflex
- Caused by abnormalities in lower motor neurons (LMN sign)

10

5 main types of somatosensation

- Position
- Vibration
- Touch
- Pain
- Temperature

11

Mechanoreceptors (types of sensation and key characteristics)

- Position, vibration, and touch
- Found at varying depths: ones in muscle for position, ones in skin for vibration + touch
- Large diameter axons; thick myelin sheath; fast signal transduction

12

Nociceptors (types of sensation and key characteristics)

- Pain
- Thin myelin sheath; slow signal transduction
- End in uncovered terminals, don't have big structures like mechanoreceptors

13

Thermoreceptors (types of sensation and key characteristics)

- Temperature
- Thin myelin sheath; slow signal transduction
- End in uncovered terminals, don't have big structures like mechanoreceptors

14

Muscle stretch reflex

- Causes a muscle to contract after it is stretched
- Hammer hits tendon below kneecap, which hooks onto the lower leg bone on one end, and a large group of upper muscles (muscle spindles) on the other
- Afferent somatosensory neurons in muscle spindles form excitatory synapse in spinal cord with another neuron in the spinal cord, which sends axon out to same muscle that was stretched, and excites skeletal muscle cells to contract
- Muscles on underside of leg are inhibited when the topside of leg is excited. Necessary for reflex to occur

15

Gray matter

- Contains most of the neuron somas
- Spinal cord: gray inside, white outside
- Brain: white inside, gray outside

16

White matter

- Contains myelinated axons
- Spinal cord: gray inside, white outside
- Brain: white inside, gray outside

17

Areas controlled by lower motor neurons

- Muscles of limbs and trunk
- LMNs that pass through cranial nerves control muscles of head and neck

18

Upper motor neurons (cell location, synapse location)

- Found in cerebral cortex
- Synapse on LMNs in brainstem or spinal cord

19

UMNs: corticospinal tract

UMN white matter pathway: cerebral cortex > down brainstem > spinal cord > axons cross and travel down other side > lower motor neurons

20

UMNs: corticobulbar tract

UMN white matter pathway: [Need to look up]

21

Upper motor signs

- Hyperreflexia
- Clonus
- Hypertonia
- Extensor plantar response

22

Hyperreflexia

- Increase in muscle stretch reflexes
- Muscle spindle receptors become hypersensitive

23

Clonus

- Rhythmic contractions of antagonist muscle
- Caused by hyperflexia (doctor pulls on foot > activates muscle stretch reflex > triggers antagonist muscles

24

Hypertonia

Increased tone of skeletal muscles

25

Extensor plantar response

- Scrape hard object along foot:
- Normal response: flexor toes come down on object
- Extensor plantar response: toes extend up

26

Cerebral cortex (4 lobes)

Frontal, parietal, occipital, temporal

27

Frontal lobe overview

- Motor cortex
- Prefrontal cortex
- Broca's area