Unit 2 - PNS, Muscle & Cardiac phys.

Question 1

photoreceptors

Answer 1

responsive to visible wavelengths of light

Question 2

mechanoreceptors

Answer 2

• sensitive to mechanical energy
• Ex. skeletal muscle receptors sensitive to stretch; receptors in ear w/fine hairs that are bent as a result of sound waves; blood pressure monitoring baroreceptors

Question 3

thermoreceptors

Answer 3

sensitive to heat & cold

Question 4

osmoreceptors

Answer 4

detect changes in the concentration of solutes in the ECF & resultant changes in osmotic activity

Question 5

chemoreceptors

Answer 5

• sensitive to specific chemicals
• include receptors for taste, smell, & those deeper in the body that detect O2 & CO2 concentrations in the blood or the chemical content of digestive tract.

Question 6

nocireceptors / aka pain receptors

Answer 6

sensitive to tissue damage (cutting or burning)

Question 7

tonic receptors

Answer 7

• do not adapt or adapt slowly
• useful when it’s valuable to maintain info @ a stimulus
• ex. muscle stretch receptors = monitor muscle length & joint proprioception to help maintain posture & balance. Impt that these do not adapt

Question 8

phasic receptors

Answer 8

• rapidly adapting receptors

- adapt by no longer responding to a maintained stimulus (ex. wearing a ring)

Question 9

Tactile (touch) receptors

Answer 9

1. hair receptor
2. Merkel’s disc - detects light, sustained touch & texture, such as Braille; is slowly adapting
3. Pacinian corpuscle - responds to vibrations & deep pressure; is rapidly adapting
4. Ruffini endings - respond to deep, sustained pressure & stretch of skin, such as during a massage; are slowly adapting
5. Meissner’s corpuscle - sensitive to light, fluttering touch, such as tickling w/a feather; is rapidly adapting

Question 10

Cerebellum

Answer 10

• important in balance & in planning & executing voluntary movement
  3 different parts:
  1. vestibulocerebellum (bottom) - balance & control of eye movement
  2. cerebrocerebellum - (middle) planning & initiation of voluntary activity by providing input to cortical motor areas also involved in procedural memories
  3. spinocerebellum (top) - enhances muscle tone & coordinates skilled voluntary movement - impt in synchronization & timing

Question 11

Brain Stem - parts

Answer 11

1. midbrain
2. pons
3. medulla

Question 12

Medulla function

Answer 12

Reticular formation - Reticular Activing System (RAS) - consists of ascending fibers that originate in the reticular formation in the medulla & carry signals upward to cerebral cortex.

Question 13

pons function

Answer 13

1. sensory and motor nuclei for 4 cranial nerves
2. nuclei that help control respiration
3. links cerebellum

Question 14

2 types of short term memory

Answer 14

1. habituation - learn to ignore indifferent stimuli. Ca+ channels do not open as readily
2. sensitization - increased response to mild stimuli following a strong stimulus
   - Ca+ entry into presynaptic terminal is enhanced

Question 15

components of Basal Nuclei:

Answer 15

1. putamen
2. caudate nuclei
3. claustrum
4. globus pallidius

Question 16

major components of limbic system

Answer 16

1. cingulate gyrus
2. hippocampus
3. amygdala
4. fornix

Question 17

role of limbic system?

Answer 17

emotions, motivation, survival

Question 18

primary function of thalamus?

Answer 18

relay sensory input to the cortex

Question 19

main functions of hypothalamus?

Answer 19

1. homeostatic control;

2. connects autonomic system with endocrine system

Question 20

major roles of cerebellum?

Answer 20

1. maintain balance;
2. control eye movements;
3. enhance muscle tone;
4. facilitate procedural memory

Question 21

3 parts of brainstem & main functions

Answer 21

1. medulla - regulate heart & respiratory rates; controls sleep/wake cycles
2. pons - controls respiration rate
3. midbrain - connects brainstem to cerebrum

Question 22

modality

Answer 22

stimuli exist in various energy forms, or modalities, such as heat, light, sound, pressure, and chemical change.

Question 23

sensory coding

Answer 23

Based on:
1. stimulus modality - type of receptor activated; pathway to cerebral cortex
2. Location - site of the stimulated receptor; precision of location (receptive field, lateral inhibition)
3. Intensity -
4 Duration

Question 24

Sensory coding: Location

Answer 24

1. Coded by site of the stimulated receptor
2. Precision of location = acuity
   - # of receptive fields / convergence
   - lateral inhibition

Question 25

Receptive fields

Answer 25

ares with less convergence will have more neurons reaching the somatosensry cortex

Question 26

circular (constrictor) muscles of eye

Answer 26

• innervated by parasympathetic system

- in bright light, constrict the pupil when contracted

Question 27

radial (dilator) muscle of eye

Answer 27

Fight-Dim-Sym

• innervated by sympathetic system
• in dim light, constrict to cause pupil to open (dilate)

Question 28

emmetropia

Answer 28

normal eye

Question 29

myopia

Answer 29

• nearsightedness
• eyeball is too long or lens too strong
  needs accommodation for far sight
  corrected w/concave lens

Question 30

hyperopia

Answer 30

• farsightedness
• eyeball is too short or lens too weak
  needs accommodation for near sight
  corrected w/convex lens

Question 31

phototransduction

Answer 31

process of converting light stimuli into electrical signals

Question 32

rhodopsin

Answer 32

• comprised of:
  
  • opsin - a membrane protein AND
  • retinal - a vitamin A derivative, bound w/in interior of opsin
• in the dark (inactivated) - retinal is 11-cis retinal
• in the light (activated - retinal changes to all-trans retinal

Question 33

Anatomy of inner ear

Answer 33

Vestibular Apparatus

• Semicircular canals
• utricle
• saccule

Cochlea

• scala vestibuli (perilymph)
• scala media (endolymph, organ of Corti)
• scala tympani (perilymph)
• basilar membrane