Chapter 8 - Thw Autonomic Nervous System Flashcards Preview

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What is the autonomic nervous system?

It is that part of the nervous system that regulates automatic body functions such as heartbeat, blood pressure and digestion. It brings about response to changes in the internal and external environment that enables homeostasis.

1

What are the two main parts of the nervous system?

Central nervous system (CNS), the control centre - brain, spinal cord.

Peripheral Nervous System (PNS) - nerves that connect the CNS with the receptors, muscles and glands.

2

What does the PNS consist of?

Nerve fibres that carry information to and from the CNS and groups of nerve cell bodies, ganglia.

3

What is Ganglia?

They are groups of nerve cell bodies, which lie outside the brain and spinal cord.

4

How are the nerve fibres arranged?

The nerve fibres are arranged into nerves that arise from the brain and the spinal cord.

5

What are Cranial Nerves?

They are 12 pairs of nerves that arise from the brain.

6

Why are Cranial nerves mixed nerves?

They contain fibres that carry impulses into the brain, as well as fibres that carry impulses away from the brain.

7

What are sensory fibres?

They are fibres that carry impulses into the CNS.

8

Why are Motor Fibres?

They carry impulses away from the CNS.

9

How many spinal nerves are there?

31 pairs.

10

What does the Ventral root contain?

It contains the axons of motor neurons that have their cell bodies in the grey matter of the spinal cord.

11

What does the Dorsal Root contain?

It contains the axons of sensory neurons that have their cell bodies in a small swelling in the dorsal root known as the dorsal root ganglion.

12

How are impulses carried into the CNS from the Afferent division?

They are carried into the CNS by sensory nerve cells from receptors in the skin and around the muscles and joints. These nerve cells from the body are called Somatic sensory neurons.

13

What is the role of the visceral sensory neurons?

They are nerve cells that take impulses from the internal organs into the CNS.

14

What does the efferent (or motor) division have?

It has fibres that carry impulses away from the CNS.

15

The efferent is subdivided into 2 divisions and they are?

1. Somatic division (sns) which takes impulses from the CNS to the skeletal muscles.

2. Autonomic division (ans), which carries impulses from the CNS to heart muscle, involuntary muscle and glands.

16

What is the Autonomic division subdivided into?

1. Sympathetic Division
2. Parasympathetic Division

17

What is the Autonomic Nervous System (ANS) responsible for?

The ANS is responsible for the control of the body's internal environment and is involved in many of the homeostatic mechanisms that keep the internal environment constant.

18

How does the Autonomic Nervous System (ANS) work?

It usually operates without conscious control and is regulated by groups of nerve cells in the medulla Oblongata, hypothalamus and cerebral cortex.

19

What are some body functions regulates by the Autonomic division include?

It includes heart rate, blood pressure, body temperature, digestion, release of energy, pupil diameter, airflow to the lungs, Defecation and urination.

20

What do the nerve fibres of the ANS make up?

It makes up part of the spinal nerves and part of some of the cranial nerves.

21

What is the role of the nerve fibres of the ANS?

They carry impulses to the heart muscle, other muscles of the internal organs and the glands.

22

What is a Ganglion?

It is a group of nerve cell bodies outside the CNS. Most nerve cell bodies are in the grey matter of the brain or spinal cord, but where they occur outside the CNS they are grouped in ganglia.

23

What is the main difference between the autonomic and somatic division?

The pathway from the CNS to heart muscle, involuntary muscle or glands.

24

How many motor neurons are involved in the autonomic and somatic division?

• Autonomic - 2 motor neurons
• Somatic - 1 motor neuron carrying impulses from the CNS to the effector.

25

List the 2 important differences between the autonomic and somatic divisions.

1. Most organs under autonomic control receive two sets of nerve fibres Sympathyic and Parasympathetic divisions.

2. In the Somatic nervous system, the neurotransmitter that carries the message from the neuron to the skeletal muscle is acetylcholine; in the ANS either acetylcholine or noradrenaline carry the message to the effector.

26

List the Effectors for Autonomic & Somatic division.

1. ANS - Heart muscle, involuntary muscle, glands

2. SNS - Skeletal (voluntary) muscles

27

List the General function for Autonomic & Somatic division.

1. ANS - Adjustment of the internal environment (homeostasis)

2. SNS - Response to the external environment

28

List the Efferent (outward) pathways for Autonomic & Somatic division.

1. ANS - Two nerve fibres from the CNS to the effector with a synapse in a ganglion.

2. SNS - One nerve fibre from the CNS to the effector; no synapse and no ganglion.

29

List the Neurotransmitter at Effector for Autonomic & Somatic division.

1. ANS - Acetylcholine or noradrenaline

2. SNS - Acetylcholine