Question

1. The nose and the tongue contain chemoreceptors. What is the required condition of the stimulus to be detected by either one of them?

2. The tongue is sensitive to several tastents. What are they? Which one will be the most sensitive to?

3. What is the visual pathway starting from the light entering the eye?

4. What is the hearing pathway starting from the sound waves entering the ear?

5. Which nerve is responsible for hearing? Which is responsible for balance (movement)?

6. What are the following conditions: A) cataracts; B) astigmatism; C) myopia; D) glaucoma; E) macular degeneration?

7. What is the effect of ear infection on taste? Why?

8. Know all routes of the sympathetic pathways and how they travel.

9. What is the effect of an epi-shot on the heart? Why?

10. Know the effect of sympathetic and parasympathetic systems on different organs.

11. What are the alternate names of the sympathetic and parasympathetic systems?

12. What is the effect of smoking on sympathetic and parasympathetic systems?

13. What is/are the organ system (s) not controlled by the ANS?

14. What are the different types of neurons in the ANS and where are they located?

Answer 1

1) Chemoreception in regards to taste,occurs via presence of specialised taste receptors within mouth,that are referred to as taste cells and are bundled together to form tastebuds.These receptors are activated when their specific stimulus ( salt / sweet) is present and signals to brain.

Like taste, sense of smell or olfaction is also reaponsible for chemical stimuli ,olfactory receptor neurons are located in small region within superior nasal cavity ,is referred as olfactory epithelium and contain bipolar sensory neuron.

2) Several tastants are sweet,sour,salty,bitter,umami/ savory.

Among them,roughly one in four people is a supertaster that is severap times more sensitive to bitter and other tastes them those that taste poorly.Back of tongue is very sensitive to bitter tastes.

3)Outside - cornea- aqueous humour- pupil - lens- vitreous humour- photoreceptors - bipolar cell layer - retinal ganglion cells - retinal ganglion cell axons - optic disc - optic head - optic nerve - optic chiasma - optic tract - superior colliculus - lateral geniculate nucleus of thalamus - primary visual cortex of occipital lobe of brain.

4) Sound travels from outer ear to auditory canal and then causes vibration in eardrum which makes three bones move in middle ear cavity and move through fluid of cochlea which is located in inner ear.

5) Vestibulocochlear nerve involved in vestibular function and is used both for hearing and balance.

6) cataracts - eye becomes progressively opaque. Resulting in blurred vision .

Astigmatism - defect in eye or lens caused by deviation from spherical curvature ,which results in distorted images as light rays are prevented from meeting at common focus.

Myopia - shortsightedness.

Glaucoma - pressure is increased in aqueous humour due to closed or open angle or any complication which causes gradual loss of sight.

Macular degeneration - degenerative condition affecting cnetral part of retina and resulting in distortion or loss of central vision .It occurs especially in older adults commonly called as age related macular degeneration.

7) It is because of chorda tympani nerve as it supplies both middle ear and anterior two thirds of nerve.

8) Cell bodies of preganglionic axons of sympathetic division are located in segments T1 through L3 of lateral horn of spinal cord.From here, these axons project away from spinal cord through ventral root and enter spinal nerve through white ramus comminicans and enter sympathetic chain ganglion which are located along spinal cord bilaterally.

4 differebt routes taken by sympathetic axons travelling from CNS to their effectors.

1 preganglionic axons synpase at sympathetic chain ganglia with postganglionic neuron.It then leaves sympathetic chain ganglia througb grey ramnus communicans and reenter spinal nerve and travels to skin and blood vessels through out body

2 2 nd type is similar but instead it enters sympathetic nerve and travels to organs of thoracic cavity.

3 preganglionic fibres enter and leave the sympathetic chain ganglia without synpasing and forms splanchnic nerve and travels to collateral ganglia.At these ganglia, the Preganglionic neurons synpase with postganglionic neuron which these extend to glands,organs,vessels of abdominopelvic cavity.

4 last route is similar to those travelling through splanchnic nerve but instaed of synpasing ,they travel straight through collateral ganglia.Then they extend to medulla of adreanl glands,where they synapse with cells that produce epinephrine and norepinephrine.

9) Symptoms of severe allergic reaction are low blood pressure, wheezing , skin itching , hives.

Epinephrine injection is used to trear those severe allergic reactions.

10)p ( Parasympathetic )

S ( sympathetic )

Heart p - decreases rate and force of contraction

S - increases rate and force of contraction

Glands p - increases secretions

S - decreases secretions

Eye p - constricts pupil

S - dilates pupil

Digestive tract p - increases motility

S - decreases motility

11) sympathetic system - thoracolumbar

Paradympathetic system - craniosacral

12) In habitual smokers , smoking actually reduces baseline levels of vagal cardiac nerve activity and completely resets vagally mediated arterial baroreceptor cardiac reflex responses.

Smoking also reduces muscle sympathetic nerve activity but increases sympathetic activity triggered by brief arterial pressure reduction .This pattern of autonomic change is likely to infulence smokers responsesto arterial pressure reduction importantly.

13) increased peristalsis of digestive viscera and skeletal muscle ( not ANS)

14) preganglionic neurons in which cell body in CNS which projects its axon to peripheral ganglion

Post ganglionic neuons in which cell body in peripheral ganglion projects its axon to an effector.