Chapter 15 & 16 - ANS & Sensory, Motor & Integrative Systems Flashcards Preview

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Flashcards in Chapter 15 & 16 - ANS & Sensory, Motor & Integrative Systems Deck (59)
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1

(2) divisions of ANS

sympathetic 

parasympathetic

2

 
Structure of the Sympathetic Division

thorocolumbar (sympathetic) division- Preganglionic neurons originate from thoracic lumbar levels of spinal cord (T1-L2). 

 

Sympathetic ganglia - site of synapse between sympathetic pre & postganglionic 

(2) types - sympathetic trunk & prevertebral (collateral) ganglia

 

3

Preganglionic & postganglionic neurons

preganglionic - cell body in CNS, exits as cranial/spinal nerve 

axon = type B fiber (small, myelinated)

postganglionic - in PNS (outside CNS), cell body & dendrites in autonomic ganglia 

axon = small, unmyelinated type C fiber 

4

Sympathetic division 

sympathetic ganglia (2) 

Sympathetic trunk (vertebral chain) ganglia. - innervate organs above diaphragm 


Prevertebral (collateral) ganglia: celiac, superior mesenteric, inferior mesenteric, 
aorticorenal and renal.

innervate organs below diaphragm

5

Once axons of sympathetic preganglionic neurons pass to sympathetic trunk ganglia, they may connect with postganglionic neurons in the following ways (4) 

1) synapse with neurons in nearest gangliaon

2) axons ascend/descend to higher/lower ganglion, sympathetic chains 

3) through sympathetic trunk ganglion to synapse with neurons in prevertebral ganglion

4) through sympathetic trunk & prevertebral to chromaffin cells of adrenal medulla 

6

A single sympathetic preganglionic fiber has many axon _______________ and may synapse with 20 or more postganglionic neurons. 

 

branches (collaterals) 

 

7

sympathetic postganglionic axons typically terminate in several 

visceral effectors 

therefore effects are more widespread than parasympathetic stimulation

8

Structure of the Parasympathetic Division 

 

craniosacral divison - Preganglionic neurons originate from cranial 
nerves III, VII, IX, X & sacral spinal nerves S2-S4

parasympathetic ganglia - preganglionic synapse with postganglionic in terminal (intramural) ganglia 

 

9

Parasympathetic Presynaptic neuron usually synapses with 4-5 postsynaptic neurons all of which supply ?

a single visceral effector

10

Autonomic Plexuses in Thorax, Abdomen & Pelvis

network of sympathetic & parasympathetic neurons 

thorax plexus - heart

pulmonary plexus - bronchial tree

celiac (solar) plexus - largest. stomach, spleen, pancreas, liver, gallbladder & adrenal medulla

11

Sympathetic response

fight or flight

 ↑ ATP, heart rate, BP, blood supply to skeletel/cardiac muscles, liver & fat, blood glucose

dilation of pupils, constriction of blood vessels 

breakdown of glycogen & lipids

12

Parasympathetic Responses

rest & digest

conserve & restore energy 

 ↑ digestive & urinary function

↓ body functions supporting physical activity 

 

13

Sensation

conscious & subconscious awareness of changes in environment 

14

components of sensation

Stimulation of sensory receptor → transduction of stimulus → nerve impulses integration of sensory input. 

 

15

Classification of Sensory Receptors

General senses

Special Senses

16

  1. General senses
  2. Special senses

1) somatic & visceral 

a. somatic - tactile, thermal, pain &proprioceptive sensations

b. Visceral- provide info about conditions within internal organs. 

2) smell, taste, vision, hearing, equilibrium/balance

17

Types of Sensory Receptors

free nerve endings

encapsulted nerve endings

seperate cells

18

free nerve endings

pain & thermoreceptors

19

encapsulated nerve endings

dendrites enclosed in CT capsule

pacinian corpuscles

20

seperate cells 

hair cells, photoreceptors & gustatory receptor cells

21

Generator Potential and Receptor Potential 

 

Generator potential: produced by free nerve, encapsulated nerve endings, and olfactory receptors. When it reaches threshold, triggers 1+ nerve impulses in axon of  first-order sensory neuron. 


Receptor potential triggers release of neurotransmitterspostsynaptic potential → action potential. 

 

22

Classification of Sensory Receptors Based on the Location

o Exteroceptors: external surface
o Interoceptors: internal environment (vessels, organs & muscles & NS) 
o Proprioceptors: muscles, tendons, joints & nner ear 

23

Classification of Sensory Receptors based on the type of Stimulus

mechanoreceptors - mechanical stimuli (touch, proprioception) 

thermoreceptors

nociceptors - pain

photoreceptors - light

chemoreceptors - chemicals in mouth, nose & body fluids

Osmoreceptors 

24

Adaptation of Sensory Receptors 

 

rapidly adapting receptors:  detect pressure, touch and smell. 

slowly adapting receptors: detect pain, body position & blood chemical composition

 

25

Somatic Sensations 

(4) modalities 

 

sensory receptors in skin, muscles, tendons, joints & inner ear 

1) tactile 

2) thermal

3) pain

4) proprioceptive 

 

26

 
Tactile Sensations 
include?

touch

pressure 

vibration

itch 

tickle

27

Tactile receptors in skin

Meissner corpuscles

hair root plexuses

Merkel discs

Ruffini corpuscles

pacinian corpuscles

free nerve endings. 

28

Meissner Corpuscles or Corpuscles of Touch 

 

egg-shaped mass of dendrites enclosed by capsule of CT

rapidly adapting 

dermal papillae of hairless skin 

 

TOUCH & PRESSURE

29

Hair root plexuses

rapidly adapting- touch 

in hairy skin

free nerve endings wrapped around hair follicles 

detect movement on skin that disturbs hair

30

Merkel Discs or Tactile Discs 

 

type I cutaneous mechanoreceptors

slowly adapting touch 

fingertips, hands, lips, external genitals