week 3

Question 1

anticholinergic drug example and side effects

Answer 1

amitriptyline
constipation, dry mouth, dry eyes, tachycardia, urinary retention, agitation, confusion,

Question 2

what is the difference between unipolar and multipolar neurons?

Answer 2

Unipolar/pseudounipolar:
Sensory neurons
Have cell body in the PNS
Have only one projection of dendrites

Multipolar:
Motor neurons
Have cell body in the CNS
Have multiple projections of dendrites

Question 3

how many pairs of spinal nerves are there?

Answer 3

31:
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal

Question 4

where are spinal nerves present?

Answer 4

in the intervertebral foramen

Question 5

how are spinal nerves named?

Answer 5

cervical named according to the vertebra BELOW
C8 comes between C7 and T1 vertebrae
cervical onwards named according to vertebra ABOVE

Question 6

explain spinal nerves, roots, rootlets, horns etc

Answer 6

Dorsal and ventral rootlets come from the ‘H’ region of the spinal cord.

all motor axons originate from the anterior horn
all sensory axons pass to the posterior horn

The rootlets converge to form larger structures called roots:
* Ventral roots –> motor (and so technically come OFF of the spinal cord)

* Dorsal roots --> sensory (and so technically go INTO the spinal cord)

Dorsal roots have a dorsal root ganglion. These contain the cell bodies of primary afferent neurons.

The dorsal and ventral roots then converge to form a spinal nerve. This has both motor and sensory elements.

The spinal nerve divides into a ventral and dorsal ramus (plural rami). These are mixed – have both motor and sensory nerve fibres.

* The posterior rami is smaller and supplies the posterior body wall

* The anterior rami is larger and supplies the anterolateral body wall

Question 7

what do spinal nerves supply their body segment with?

Answer 7

general sensory supply
somatic motor supply to skeletal muscles
sympathetics to skin, arteriole smooth muscle

Question 8

what part of the spinal nerve are nerve plexuses formed of?

Answer 8

the anterior rami

Question 9

name the 4 bilateral nerve plexuses, their nerve roots and what they supply

Answer 9

cervical plexus: C1-4
posterior scalp, neck and diaphragm

brachial plexus: C5-T1
upper limb

lumbar plexus: L1-4
lower limb

sacral plexus L5-S4
lower limb, gluteal region and perineum

Question 10

describe the sympathetic chain

Answer 10

Control centres in the brain send signals down the spinal cord. These travel in the sympathetic chain: two chains on either side of the vertebrae across its entire span. It is also known as the prevertebral chain.

The sympathetic information traveling in the chain can only exit via the lateral horn (T1-L2). This is why sympathetic innervation is also known as thoracolumbar outflow.

information exits the lateral horn via a ventral root, then enters the sympathetic chain via a white ramus communicantes. if there is a synapse within the chain, the info leaves the chain via a gray ramus communicans to rejoin the spinal nerve

Question 11

what happens to neurons that pass through the sympathetic chain without synapsing?

Answer 11

Greater/lesser/least/lumbar/sacral splanchnic nerves then travel to and synapse at prevertebral ganglia in the abdomen. these are nerve networks around the abdominal aorta and its branches (coeliac plexus, aortico-renal plexus, sup/inf mesenteric plexuses)

travel directly to the adrenal medulla and synapse with chromaffin cells

Question 12

describe the sympathetic innervation of the heart

Answer 12

• Presynaptic axons synapse in T1 or travel up to synapse at cervical paravertebral ganglia (symp chain)
• Post synaptic axons go to via cardiopulmonary splanchnic nerves to the SA and AV nodes and the myocardium

Note: this is an exception to the concept that splanchnic nerves do not synapse in the sympathetic chain

Question 13

describe the sympathetic innervation of the lungs

Answer 13

• Presynaptic axons synapse in the upper thoracic paravertebral ganglia
• Post synaptic axons go via cardiopulmonary splanchnic nerves to the bronchiolar smooth muscles and mucous glands

Question 14

what are the ganglia that splanchnic nerves synapse on for each region of the gut’s sympathetic innervation?

Answer 14

foregut: coeliac ganglion
midgut: superior mesenteric ganglion
hindgut: inferior mesenteric ganglion

Question 15

nerve roots for greater, lesser and least splanchnic nerve

Answer 15

Greater splanchnic nerve = T5-9
Lesser splanchnic nerve = T10-11
Least splanchnic nerve = T12

Question 16

describe how parasympathetic innervation arises

Answer 16

Pre-synaptic parasympathetic axons exit the CNS via:
- CN III
- CN VII
- CN IX
- CN X
- Sacral spinal nerves

eye: travel via ciliary ganglion
neck organs, chest and abdomen as far as mid-gut: vagus nerve

hindgut, pelvis, perineum: sacral spinal nerves

Question 17

what is global health?

Answer 17

Global health involves a focus on improving health and achieving health equity worldwide. This is done by targeting transnational issues on a population-based scale in a collaborative and interdisciplinary manner.

Question 18

does x-linked inheritance affect females?

Answer 18

on rare occasions
random X inactivation
turner’s syndrome