Nervous system

Question 1

What is a neuron

Answer 1

basic structural unit of the nervous system.

Highly specialised cell that conduct electrical signals along axons.

Question 2

What are the oligodentrocytes

Answer 2

• the myelinating cell of the CNS

- - can myelinate several axons

Question 3

What does myelin do?

Answer 3

Tightly wraps around the cell membrane

Myelin basically represents fat

Question 4

Contrast ‘white matter’ to ‘grey matter’

Answer 4

white matter: fat is pale/yellow characterizing areas of the CNS with higher myelination
Grey matter: composed of less myelinated axons (higher density of cell bodies)

Question 5

Describe meninges: Pia mater

Answer 5

closest layer to brain, follows all irregularities of brain surface

Question 6

Describe meninges: Arachnoid mater

Answer 6

Subdural layer with projections to pia (forms subarachnoid space for CSF)

Question 7

Describe meninges: dura mater

Answer 7

external dense connective tissue (protection)

Question 8

What are the dural folds?

Answer 8

• divide the cranial cavity and help to hold the brain in place
• houses the venous sinuses

Question 9

what comprises the forebrain?

Answer 9

• cerebrum

- thalamus, hypothalamus (Diencephalon)

Question 10

What comprises the midbrain

Answer 10

• narrow connection of forebrain to hindbrain

- contains cerebral aqueduct

Question 11

What comprises the hindbrain

Answer 11

• medulla oblongata
• pons
• cerebellum

Question 12

What are the folds of the brain called?

Answer 12

Gyri (singular = gyrus)

Question 13

What are the grooves of the brain called

Answer 13

Sulci (singular = sulcus)

Question 14

Describe the following features of the somatic section of the nervous system:
CONTROL
EFFERENTS
EFFECTOR ORGANS
EFFECT

Answer 14

CONTROL: voluntary, 1 neuron from spinal cord
EFFERENTS: cell body in VENTRAL grey horn or motor cranial nerve nuclei in the brainstem
EFFECTOR ORGANS: Skeletal muscle
EFFECT: excitation

Question 15

Describe the following features of the autonomic section of the nervous system:
CONTROL
EFFERENTS
EFFECTOR ORGANS
EFFECT

Answer 15

CONTROL: involuntary, 2 neurons from brain stem/spinal cord
EFFERENTS: 1st cell body in LATERAL grey horn or motor cranial nerve nuclei in the brainstem, 2nd cell body in peripheral ganglia
EFFECTOR ORGANS: smooth and cardiac muscle; secretory glands
EFFECT: excitation or inhibition

Question 16

What are the two sections of the autonomic cernous system and what do they cause?

Answer 16

Sympathetic: preparation for emergency
FIGHT OR FLIGHT

Parasympathetic: conserving/ restoring energy
REST AND DIGEST

Question 17

What is the general layout of Autonomic Pathways?

Answer 17

preganglionic cell body in CNS - lateral horn or brainstem –> preganglionic axon (myelinated) –> Autonomic ganglion –> postganglionic axon (unmyelinated) –> effector organ

Question 18

Right the generalised structure of a parasympathetic division neuron

Answer 18

Preganglionic neuron –> long preganglionic axon –> autonomic gamglion –> ganglionic neuron –> short postganglionic axon

Question 19

Right the generalised structure of a sympathetic division neuron

Answer 19

Preganglionic neuron –> Short, branching preganglionic axon –> autonomic ganglion –> ganglionic neuron –> long postganglionic axon

Question 20

Write the effects of the sympathetic and parasympathetic division on the heart

Answer 20

S - inc. HR, inc. forced contraction, inc. BP

PS - dec. HR, dec. force contraction, dec. Blood pressure

Question 21

Write the effects of the sympathetic and parasympathetic division on the eye

Answer 21

S - dilate pupil

PS - constrict pupil

Question 22

Write the effects of the sympathetic and parasympathetic division on the airways

Answer 22

S - inc. airway diameter

PS - dec. airway diameter

Question 23

Write the effects of the sympathetic and parasympathetic division on the blood vessels

Answer 23

S - dec. GIT blood flow, inc. skeletal muscle blood flow

PS - not innervated

Question 24

Write the effects of the sympathetic and parasympathetic division on the GIT glands

Answer 24

S - inhibition e.g. dec. insulin production (pancreas)

PS - stimulation e.g. inc. insulin production (pancreas)

Question 25

Describe the transmission, chemical mediators and distribution effects of direct communication

Answer 25

TRANSMISSION: through gap junctions CHEMICAL MEDIATORS: ions, small solutes, lipid-soluble materials EFFECTS: usually limited to adjacent cells of the same type

Question 26

Describe the transmission, chemical mediators and distribution effects of paracrine communication

Answer 26

TRANSMISSION: through extracellular fluid CHEMICAL MEDIATORS: paracrine factors DISTRIBUTION EFFECTS: limited too local area. Target cells must have appropriate receptors

Question 27

Describe the transmission, chemical mediators and distribution effects of endocrine communication

Answer 27

TRANSMISSION: through the circulatory system CHEMICAL MEDIATORS: hormones EFFECTS: target cells are primarily in other tissues and organs and must have appropriate receptors

Question 28

What are conditions of the chemical mediator being hormones?

Answer 28

they are: - slower to act (minutes to hours) - can have multiple targets - tends to act for longer periods of time as must be removed from blood stream - sometimes stockpiled in blood on transporter molecules

Question 29

Describe the transmission, chemical mediators and distribution effects of synaptic communication

Answer 29

TRANSMISSION: across synaptic clefts CHEMICAL MEDIATORS: neurotransmitters EFFECTS: limited to very specific areas. target cells must have appropriate receptors

Question 30

What are the conditions of the chemical mediators being neurotransmitters?

Answer 30

- immediate action | - fast to turn on/off

Question 31

List the 10 major endocrine organs

Answer 31

- pineal gland - hypothalamus - pituitary gland - thyroid gland - parathyroid glands - thymus - adrenal glands - pancreas - ovary - testis

Question 32

What two hormones does the posterior pituitary secrete and what do they do?

Answer 32

Antidiuretic hormone (ADH): stimulates kidney to reclaim water from urine, raises blood pressure. Oxytocin: female reproductive stimulation

Question 33

Name the seven hormones released by the anterior pituitary gland

Answer 33

- Growth hormone (GH) - Thyroid stimulating hormone (TSH) - Prolactin (PRL) - Adrenocorticotropic hormone (ACTH) - Melanocyte-stimulating hormone (MSH) - Follicle-stimulating hormone (FSH) - Lutenizing hormone (LH)

Question 34

Where does growth hormone target

Answer 34

- mitosis cells | - liver to produce another hormone

Question 35

What does thyroid stimulating hormone do?

Answer 35

regulated release of thyroid hormone from the thyroid hormone

Question 36

describe the adrenal glands

Answer 36

- each adrenal gland is 2 endocrine glands in one - adrenal medulla is more like a cluster of neurons. - Secrets adrenalin and noradrenalin - Adrenal cortex (3 layers) secretes steroid hormones (lipid base): corticosteroids and sex hormones

Question 37

What does the exocrine (Acinar cells) do?

Answer 37

- for most of the pancreas | - secrete pancreatic juices (digestive enzymes) into the duodenum for digestion

Question 38

Describe the structure and function of the endocrine (islets of langerhans) in the pancreas

Answer 38

- alpha cells secrete glucagon - breakdown glycogen into gloucose - beta cells secrete insulin - cells take up glucose and storage of glucose as glycogen in the liver