Peripheral Nervous System (PNS)

Question 1

What does PNS consist of

Answer 1

• Consists of nerve fibres that carry information to and from the CNS and groups of nerve cell body’s called ganglia
• Nerve fibres make up nerves from the Brain & Spinal Cord
  12 pairs of nerves from brain – Cranial nerves
  31 pairs of nerves from the spinal cord – Spinal nerves

Question 2

Compare the effect of the sympathetic stimulation and the parasympathetic stimulation on the heart, lungs, stomach and intestines

Answer 2

HEART
- sympathetic nervous system increases the rate and strength of the contraction.

• Parasympathetic nervous system decreases the rate and strength of contraction

LUNGS
- Sympathetic nervous system dilates bronchioles

• Parasympathetic Nervous system constricts the bronchioles.

STOMACH AND INTESTINES
-sympathetic nervous system decreases movement in the stomach and intestines

• parasympathetic nervous system increases the movement in the stomach and intestines.

Question 3

Compare the effect of the sympathetic stimulation and the parasympathetic stimulation on the liver and iris of the eye

Answer 3

LIVER
- sympathetic nervous system increases the breakdown of glycogen and release of glucose

• parasympathetic nervous system increases uptake of glucose and synthesis of glycogen

IRIS OF THE EYE
- sympathetic nervous system dilates the pupil

• parasympathetic constricts the pupil

Question 4

Compare the effect of the sympathetic stimulation and the parasympathetic stimulation on the sweat glands, salivary glands

Answer 4

SWEAT GLANDS
- sympathetic nervous system increases sweat secretion

• parasympathetic nervous system has no effect

SALIVARY GLANDS
- sympathetic nervous system decreases the secretions of saliva

• parasympathetic nervous system increases secretion of saliva

Question 5

Compare the effect of the sympathetic stimulation and the parasympathetic stimulation on the blood vessels of skin, blood vessels of skeletal muscles and blood vessels of organs

Answer 5

BLOOD VESSEL FOR SKIN
- sympathetic NS constricts blood vessels

• parasympathetic NS has little effect

BLOOD VESSELS FOR SKELETAL MUSCLE
- sympathetic NS dilates blood vessels

• parasympathetic NS has no effect

BLOOD VESSELS FOR INTERNAL ORGANS
- sympathetic NS constricts vessels except the heart and lungs

• parasympathetic NS has little effect

Question 6

Compare the effect of the sympathetic stimulation and the parasympathetic stimulation on the urinary bladder and adrenal medulla

Answer 6

URINARY BLADDER
-sympathetic NS relaxes muscles of wall

• parasympathetic NS constricts muscles of wall

ADRENAL MEDULLA
- sympathetic NS stimulates hormone secretion

• parasympathetic NS has no effect

Question 7

What is the fight or flight response?

Answer 7

• The response to threatening situations in which the balance between the sympathetic and parasympathetic nervous system stimulation is disrupted.

The sympathetic nervous system becomes dominant
- Secretion of sweat, heart rate and depth, breathing rate etc all increase.

• prepares the body for increased activity

Question 8

What is the Afferent division of the nervous system and the divisions?

Answer 8

• The part of the peripheral nervous system which carries information to the central nervous system.
• split into two

somatic sensory divsion
- sensory neurons from skin and muscle

Visceral sensory division
- sensory neurons from internal organs

Question 9

What is the efferent division of the nervous system and the divisions?

Answer 9

• The part of the peripheral nervous system which carries information away from the central nervous system.

split into two

somatic division
- Carries messages to the skeletal muscles

Autonomic division
- Carries messages to the heart and involuntary muscles and glands
- Autonomic is split into the sympathetic and parasympathetic nervous system