Nervous system

Question 1

What layers is the meninges made of

Answer 1

From most out to in=
-Dura matter
-Arachnoid
-Pia mater

Question 2

Where is the CSF located

Answer 2

Space between Arachnoid
and Pia mater

Question 3

What cells maintain the blood-brain barrier (BBB)?

Answer 3

Astrocytes

Question 4

Why is adaptive immunity impaired in the CNS?

Answer 4

There are no dendritic cells (DCs) and the CNS lacks effective lymphatic drainage, leading to low immune cell trafficking and poor antibody entry.

Question 5

What is the Autonomic system composed of.

Answer 5

Sympathetic – “fight or flight”
Parasympathetic – “rest and digest”

Question 6

Explain the different types of neuroglia and function

Answer 6

1)Astrocytes: Assistance, support and nourishment to neurons.
2) oligodendrocytes: produce myelin sheath in cns and Shwann cells in PNS
3)Microglia: immune protection. Macrophages of NS

Question 7

How does myelination change from birth to adulthood, and what is its role in development?

Answer 7

Myelination is low at birth, rapidly increases in the first 2 years (important for milestones like walking and talking), and then gradually tapers off until about age 30. Myelin helps speed up signal transmission in neurons.

Question 8

What happens when the myelin sheath or axon is damaged, and how do they differ in repair?

Answer 8

Repairable over a period of 1-3 months with return of function
-remyelination tends to be weaker/thinner layer

Question 9

Damage to axon?

Answer 9

Poor or no repair tends to Occur – if myelin sheath still there it can guide repair and aid in axonal regeneration
-regrowth may still not occur or branch in another direction/path.

Question 10

Difference between gray and white matter

Answer 10

-Grey matter is more external (neuronal cell bodies/synapses, astrocytes and microglia)
-White matter has more central distribution (axons and oligodendrocytes)
-afferent nerves (sensory): Transmits impulses to the nervous system
-efferent nerves (motor): Transmits impulses from brain or spinal cord to muscle

Question 11

what does Cerebral Cortex do

Answer 11

receives sensory input and initiates voluntary motor responses

Question 12

What does Brain Stem do

Answer 12

involved in control of vital functions not under voluntary control (cardiac/respiratory regulation and function) and connects cortex to cerebellum

Question 13

What is A reflex arc

Answer 13

neural pathway that allows a fast, automatic response to a stimulus without involving the brain.

Question 14

What are the two different types of reflex arcs.

Answer 14

-Autonomic reflexes: Affect organs (like controlling heart rate, breathing, and digestion).
-Somatic reflexes: Involve muscles (like a muscle contracting in response to a stretch).

Question 15

What aids in the neutral buoyancy of the brain

Answer 15

choroid plexus in each ventricle produces CSF

Question 16

What ensures a steady blood supply to the brain.

Answer 16

Arterial blood supply: Large blood vessels enter the base of the skull and form a circle at the brain’s base called the Circle of Willis.

Question 17

Where is blood drained from the brain then where does it go?

Answer 17

venous sinuses in the dura mater. jugular veins to return to the heart.

Question 18

What dies Pyramidal system do

Answer 18

Controls voluntary movements, like moving your arm or leg, by sending signals directly from the brain to the muscles.

Question 19

What does Extrapyramidal system do

Answer 19

Controls involuntary movements like muscle coordination, balance, and reflexes. It helps regulate muscle groups for actions like walking, maintaining posture, and responding to stimuli without conscious effort.

Question 20

Difference between muscle tone Flaccid tone and spastic tone

Answer 20

-Muscle tone is controlled by reflex arcs, which are automatic and don’t need direct control from the brain, but can still be influenced by higher brain activity.

-Flaccid tone means muscles are too relaxed (lack of muscle tone)
-spastic tone means muscles are too tight (excess muscle tone).

Question 21

Explain different types of paralysis

Answer 21

Flaccid paralysis: occurs when there is damage to the PNS, usually due to disease, like poliomyelitis. The damage affects the lower motor neurons or the reflex arc responsible for muscle control. Without nerve signals, the muscle becomes weak, loses tone, and eventually atrophies (shrinks).

Spastic paralysis: This happens when there is damage to the (CNS), such as from a stroke. The reflex arc is still intact, so the muscles remain innervated (still have nerve connections), but the signals from the brain (cortex) to control the muscles are lost. This leads to increased muscle tone, making muscles tight and stiff. The normal balance of muscle control is disrupted because the brain’s inhibitory signals are no longer functioning properly.

Question 22

During embryonic development, the central nervous system (CNS) forms from the?

Answer 22

ectoderm.

Question 23

explain how the development of nervous system happens.

Answer 23

1.The ectoderm thickens to form the neural plate.
2.The neural plate folds into neural folds, which fuse to create the neural tube by week 4, filled with CSF.
3.Fusion starts in the hindbrain, then moves to the midbrain and forebrain, with the spinal cord forming at the other end.
4.Cerebral hemispheres develop from the forebrain, while the cerebellum and medulla develop from the hindbrain.

Question 24

The most common congenital malformations of the nervous system

Answer 24

spina bifida and anencephaly.

Question 25

Explain Anencephaly

Answer 25

happens when the upper part of the neural tube (the part that forms the brain) fails to close. This causes the brain tissue to be exposed and degenerate into a mass of vascular connective tissue mixed with damaged nervous tissue.

Question 26

How does Congenital hydrocephalus occure

Answer 26

blockage or abnormality in the brain’s ventricle system, often linked to spinal tube defects

Question 27

How does aquiered congenital hydrocephalus occur.

Answer 27

Acquired hydrocephalus occurs later in life due to tumors, adhesions (e.g., from meningitis), or trauma, which block CSF flow. It can also result from CSF overproduction.
The ventricles dilate, but the head doesn’t enlarge because the skull is fused. Symptoms include increased intracranial pressure (ICP),

Question 28

Explain the 3 different types of physical head injuries that impact the brain.

Answer 28

-Concussion
-Chronic Traumatic Encephalopathy (CTE): repeated injury can cause long lasting damage and chronic effects – associated with depression and neurodegenerative brain disorders later in life
-Contusions (bruise) more severe blow to head.

Question 29

Explain what happens in Epidural hemorrhage

Answer 29

Occurs between the dura and skull, often from skull fractures. If an artery is torn, blood fills the space quickly, forming a hematoma that can compress the brain. If not treated, it can cause brain damage or death.

Question 30

Explain Subdural hemorrhage

Answer 30

Happens between the dura and arachnoid layers. It develops slowly, since it’s from a vein, and can appear even months after an injury.

Question 31

Explain Subarachnoid hemorrhage

Answer 31

Occurs between the arachnoid and pia layers, either from trauma or the rupture of a cerebral aneurysm.

Question 32

List the types of hemmorages

Answer 32

-Epidural hemorrhage
-Subdural hemorrhage
-Subarachnoid hemorrhage

Question 33

Name and explain the 3 different types of strokes.

Answer 33

1)Cerebral thrombosis: The most common type, where a cerebral artery is blocked by a blood clot formed in an artery narrowed by arteriosclerosis.

2)Cerebral embolus: Less common, caused by a blockage from a fragment of arterial plaque or a blood clot that travels from the heart (due to conditions like a past heart attack or atrial fibrillation).

3)Cerebral hemorrhage: The most severe type, caused by the rupture of a cerebral artery, often due to high blood pressure.

Question 34

Explain different types of infarcts

Answer 34

Ischemic infarct: No blood leaks into brain (more common with thrombotic infarct)
Hemorrhagic infarct: Blood leaks into damaged brain tissue (embolic, aneurysm infarct)

Question 35

What is Most serious type of stroke

Answer 35

cerebral hemmorage: usually from rupture of a cerebral artery in person with hypertension
Blood escapes under high pressure and causes rapid- extensive damage (fatal)

Question 36

What is the term used to refer to mini stroke

Answer 36

Transient Ischemic Attack (TIA)

Question 37

What can result from Transient Ischemic Attack (TIA)

Answer 37

Multi-infarct vascular dementia results from cumulative brain damage from small strokes and is the second most common cause of dementia. It’s treated by managing underlying conditions, like hypertension.

Question 38

give an example of what fatal subarachnoid hemorrhage does

Answer 38

cerebral aneurysm

Question 39

explain difference between meningitis and enchiphilits

Answer 39

Meningitis: Infection affecting meninges (stiff neck/headache/fever vomiting)
Encephalitis: Infection of brain tissue (altered LOC and neurologic symptoms depending on brain area)

Question 40

How is CNS infection diagnosed

Answer 40

by testing CSF for elevated WBC and protein in presence of infection:

Question 41

What are the signs of viral infection in ns

Answer 41

if the WBCs in the CSF are mostly lymphocytes,

Question 42

What are the signs of bacterial infection in ns

Answer 42

If the WBCs are mostly neutrophils, it indicates a bacterial infection.

Question 43

what is Meningitis caused by

Answer 43

Meningococcus (Neisseria meningitidis) or Pneumococcus (Streptococcus pneumoniae)

Question 44

explain difference bettween viral meningitis and encephilits.

Answer 44

Viral meningitis (also called aseptic meningitis) causes mild symptoms like fever, stiff neck, and headache. It’s usually not serious and people typically recover completely.

Viral encephalitis involves brain tissue and is much more severe. It can cause confusion, coma, and can be fatal (e.g., rabies has nearly 100% fatality).

Question 45

What does rabbis do to the body

Answer 45

Destroys brain stem and causes severe encephalitis

Question 46

Eplain Arboviruses

Answer 46

Arboviruses are transmitted by mosquitoes and cause meningitis and encephalitis. They include viruses like Zika, which can cause microcephaly and neurological problems in newborns

Question 47

Explain prion disease

Answer 47

Caused by small protein particle produced as a result of gene mutation

Question 48

Explain prions and associated diseases

Answer 48

misfolded proteins, no immune response as they dont trigger inflamamtion.
-Kuru
-Creutzfeldt-Jakob Disease (CJD)

Question 49

What happens in Multiple sclerosis

Answer 49

where activated T lymphocytes and monocytes attack myelin proteins, leading to the destruction of the myelin sheath in the brain and spinal cord

Question 50

explain what parkisons

Answer 50

involves the loss of dopamine-producing neurons in the substantia nigra, a brain area crucial for motor control.

Question 51

What is Huntington’s disease

Answer 51

hereditary autosomal dominant disorder. It results from an abnormal gene with excessive CAG repeats—the more repeats, the earlier the onset, typically between ages 30-50. The disease causes progressive mental decline and involuntary jerky movements due to atrophy of basal ganglia neurons, which control muscle coordination. In late stages, it leads to dementia, and death occurs within 15-20 years. There is no cure, though medications can help manage some symptoms.

Question 52

explain In Lou Gehrig’s disease (ALS)

Answer 52

the motor neurons that send signals from the brain to the muscles start to break down. This causes the muscles to weaken and stop working properly.

Question 53

What does Ataxia mean

Answer 53

Ataxia refers to a group of over 25 genetic diseases that affect motor control and coordination, caused by the degeneration of neurons. Symptoms include poor coordination, difficulty with movement and speech, muscle weakness, and paralysis. There is no specific treatment.

Question 54

What is term used to refer to A gradual loss of movement over several years.

Answer 54

Spinocerebellar ataxias (SCA)

Question 55

What is the term used to refer Progressive loss of movement starting in the teens, typically fatal by age 45.

Answer 55

Friedreich ataxia (FA)