spinal and autonomic nervous system

Question 1

what is the spinal cord?

Answer 1

a structure of the CNS formed by bundles of neurons and neuroglia that are protected by the meninges and enclosed within the vertebral column.

Question 2

what does the spinal cord transport signals between?

Answer 2

the brain and the rest of the body and controls reflexes.

Question 3

where do the dorsal and ventral roots of the spinal nerves arise from?

Answer 3

The dorsal roots arise from the posterior side, and the ventral roots arise from the anterior side

Question 4

where do spinal nerves originate from?

Answer 4

the spinal cord

Question 5

after leaving the vertebral column what happens to the spinal nerves?

Answer 5

After leaving the vertebral column, the spinal nerves divide into rami, which branch to supply the body.

Question 6

Each spinal nerve connects to the spinal cord through a dorsal and ventral root. what does the dorsal root also include?

Answer 6

The dorsal root also includes a ganglion, a collection of cell bodies of the sensory neurons

Question 7

what do dorsal roots transmit?

Answer 7

dorsal roots transmit sensory signals

Question 8

what do ventral roots transmit?

Answer 8

ventral roots transmit motor signals.

Question 9

what is the spinal cord made up of?

Answer 9

white and grey matter

Question 10

how are sensory signals passes onto the spinal cord?

Answer 10

sensory signals are passes onto the spinal cord through the dorsa; root of each spinal nerve.

Question 11

state

Answer 11

Motor commands pass from the spinal cord through the central root of each spinal nerve and out to the body to trigger an action. This action is either skeletal muscle contraction or gland secretion

Question 12

what can the peripheral nervous system be further subdivided into?

Answer 12

the autonomic nervous system and the somatic nervous system.

Question 13

what does the autonomic nervous system do?

Answer 13

communicates with internal organs and glands.

Question 14

what does the somatic nervous system do?

Answer 14

communicates with sense organs and voluntary muscles

Question 15

what are the two types of autonomic nervous system?

Answer 15

sympathetic division (arousing) and parasympathetic division (calming).

Question 16

what are the two types of somatic nervous system?

Answer 16

sensory (afferent) nervous system (sensory input). and Motor (efferent) nervous system (motor output).

Question 17

what is a nerve plexus?

Answer 17

A nerve plexus is a network of intersecting nerve fibres consisting of nerves that serve the same part of the body.

Question 18

what groups are the spinal nerves divided into?

Answer 18

The spinal nerves are divided into 8 pairs of cervical nerves, 12 pairs of thoracic nerves, 5 pairs of lumbar nerves and 5 pairs of sacral nerves.

Question 19

what is dermatomes?

Answer 19

A region of the skin that is innervated by the sensory fibres from a single spinal nerve.

Question 20

state

Answer 20

Sensory signals travel from the skin through the dorsal root of the spinal nerve, into the spinal cord, and up to the brain. All the sacral, lumbar, thoracic, and cervical spinal nerves innervate dermatomes except the first cervical spinal nerve, which does not contain any sensory axons. Instead, the sensory information from the skin of the facial regions is conveyed by cranial nerve V, the trigeminal nerve.

Question 21

what are the major nerves of the Cervical plexus?

Answer 21

Major nerves of the cervical plexus include the transverse cervical, great auricular, lesser occipital, supraclavicular, and phrenic nerves.

Question 22

cervical innervation

Answer 22

the cervical plexus innervates skin and muscles of the neck. The phrenic nerves innervate the diaphragm.

Question 23

state

Answer 23

the upper part of the brachial plexus is divided into trunks, divisions and cords

Question 24

brachial innervation 1

Answer 24

brachial plexus nerves that innervate the shoulder and upper back include the dorsal scapular, suprascapular, subscapular, thoracodorsal and axillary nerves.

Question 25

Brachial innervation 2

Answer 25

brachial plexus nerves that innervate the chest and arm include the medical pectoral, lateral pectoral, musculocutaneous, and subclavius nerves.

Question 26

Brachial innervation 3

Answer 26

brachial plexus nerves that innervate the forearm and hand include the median, radial, ulnar and medical antebrachial cutaneous nerves.

Question 27

Lumbosacral plexus 1

Answer 27

major nerves of the upper lumbosacral plexus include the Ili hypogastric, ilioinguinal, genitofemoral, femoral, obturator, and lateral femoral cutaneous nerves.

Question 28

Lumbosacral plexus 2

Answer 28

major nerves of the lower lumbosacral plexus include the sciatic, gluteal, pudendal, posterior femoral cutaneous, tibial and fibular nerves.

Question 29

Lumbosacral innervation

Answer 29

the lumbosacral plexus innervates skin and muscles of the abdomen, hip, pelvis, leg, and foot.

Question 30

what are somatic reflexes?

Answer 30

Somatic reflexes are automatic responses to stimuli that allow for fast reactions, before messages reach the brain. These reflex actions occur in a series of steps known as the reflex arc.

Question 31

what are the three stages of a somatic reflex arc?

Answer 31

1. A sensory receptor detects a stimulus and a signal travels through afferent neurons towards the spinal cord.
2. When the signal passes through the grey matter of the spinal cord, a message is relayed from the afferent neuron through an association neuron to an efferent neuron.
3. This leads to a quick, automatic reflex reaction that occurs without the need for processing in the brain.

Question 32

what is the path of a reflex arc?

Answer 32

the signal passes from the receptor through the spinal nerve and dorsal root into the spinal cord, where It is processed. A motor signal is then sent from the spinal cord through the ventral root into a motor neuron.

Question 33

what does the autonomic nervous system control?

Answer 33

The autonomic nervous system controls involuntary visceral activities like heart rate, respiration, digestion, glandular secretions and reproduction

Question 34

what parts of the brain are the main centres of control of autonomic nervous functions?

Answer 34

The hypothalamus and brain stem are the main centres in control for these functions.

Question 35

state

Answer 35

All autonomic functions are managed by nerves that activate daily processes (eating, breathing, etc.) or nerves that manage the need for increased activity. (fight or flight response).

Question 36

what does the sympathetic nervous system do?

Answer 36

The sympathetic nervous system ramps up body functions during periods of increased activity

Question 37

where do sympathetic nerves arise from?

Answer 37

Sympathetic nerves arise from the thoracic and lumbar segments of the spinal cord.

Question 38

state

Answer 38

Preganglionic nerve fibres pass signals from the spinal cord to the sympathetic trunk ganglia. After synapsing, they become postganglionic fibres, and pass the signals on to their target organs.

Question 39

what is the sympathetic nervous functions?

Answer 39

The sympathetic nervous system produces the flight-or-flight response during stressful situations.

The pupils, airways, and blood vessels to skeletal muscles dilate, heart rate increases, and digestive activities are put on hold. Sweat gland secretion is also a sympathetic nervous system response.

Question 40

what does the parasympathetic nervous system activate?

Answer 40

Activates resting processes like digestion and waste elimination.

Question 41

where do parasympathetic nerves originate?

Answer 41

Parasympathetic nerves originate in the brain stem and the sacral spinal cord. Preganglionic nerve fibres synapse with postganglionic fibres which pass the signals on to their target organs.

Question 42

parasympathetic nervous functions

Answer 42

The parasympathetic nervous system is active during times of rest. Digestive and urinary activities take place, heart rate decreases, and airways decrease in diameter.