Patho & Pathophis week 1

Question 1

What are the layers of the meninges

Answer 1

Dura mater
Arachnoid mater
Pia mater

Question 2

What is the largest Foramen (hole in the skull)

Answer 2

Foreman Magnum (where the spinal cord connects to the brain)

Question 3

What are the different lobes of the brain

Answer 3

Frontal
Parietal
Occipital
Temporal

Question 4

Where is CSF made and stored in the brain

Answer 4

CSF is made in the meninges of the brain and stored in the vesicles of the brain

Question 5

How many major arteries provide the brain with blood

Answer 5

4
2 internal carotid arteries divide from common carotid artery
2 vertebral arteries join to forms a single basilar artery

Question 6

Where do the arteries in the brain interconnect?

Answer 6

The circle of Willis’
The acts as a roundabout providing the blood with more than one route ensuring the brain can get good blood flow if there was a blockage to form

Question 7

How many cranial nerves are there

Answer 7

12
The Vegal nerve is interconnected to the parasympathetic nervous system and helps slow down heart rate.

Question 8

What is the Reticular activating system (RAS)

Answer 8

This system is a diffuse network of nerve networks in the brain stem connecting the spinal cord cerebrum, cerebellum & brain stem mediating over all LOC

Question 9

What are the 2 groups TBI’s can be classified into?

Answer 9

Primary: Damage is caused by the impact of the injury itself
Secondary: Damage can be caused by swelling of the brain, skull fractures, infection or hypoxia

Question 10

What signifies a Focal injury?

Answer 10

Focal injuries occur at specific parts of the brain (usually associates with BLUNT FORCE trauma)

Question 11

What classifies a cerebral contusion

Answer 11

This comes from BLUNT trauma to local brain tissue causing CAPILLARY bleeding (Usually associates with coup/countercoup)

Question 12

What is Coup & Countercoup

Answer 12

Coup is where the brain hits the side of the skull in which directional way the injury occurred countercoup is the brain rebounding and hitting the other side of the skull

Question 13

How many types of Focal Hemorrhage are there

Answer 13

4

Question 14

What classifies a Epidural hematoma

Answer 14

This is bleeding between the Dura mater & the Skull. This often involved ARTERIAL vessels often being the meningeal artery. This is usually caused by a skull fracture.

Question 15

What classifies a Subdural Hematoma

Answer 15

This bleed happens between the DURA & ARACNOID mater.
These are usually VENOUS bleeds
These usually end up with secondary oedema and increased ICP resulting in LOC & neurological determination.

Question 16

What classifies a Subarachnoid bleed

Answer 16

This bleed happens between the Arachnoid & Pia mater.
This usually is an ATERIAL bleed and can result in decreased LOC in trauma cases

Question 17

What classifies a Intracerebral bleed

Answer 17

This is a ruptured blood vessel in the brain tissue itself. They can happen anywhere but are typically found in the Frontal & Temporal lobes.
These bleeds are usually associates with Coup & Countercoup injuries.
Usually there is minimal blood loss but the secondary injuries are damaging due to the oedema and raise in ICP

Question 18

What classifies a Concussion

Answer 18

This is a transient neurogenic dysfunction caused by a mechanical force

Question 19

Can a concussion cause amnesia?

Answer 19

Yes!

Question 20

What classifies a DIA

Answer 20

Diffuse Axonal Injuries involves tearing/disruption of axonal fibers in the white matter and brain stem.
This is usually a cause of Rotational injuries and can be grouped into MILD, MODERATE & SEVERE

Question 21

What are some causes of secondary brain injuries

Answer 21

Ischemia (lack of blood most common cause)
Cerebral hypoxia (lack of 02)
Hypotension
Cerebral oedema
Raised ICP
Hypo/hypercapnia (CO2)
Infection

Question 22

What is the CNS ischemic response

Answer 22

Question 23

What is CPP

Answer 23

This is the arterial blood pressure of the brain (the more CPP the more 02 perfusing the brain tissue.
Normal range is 70-100mmHg
Brain ischemia develops Below 40mmHg

Question 24

What is the Cushing reflex/triad

Answer 24

Question 25

What is the CNS ischemic response

Answer 25

1. contusion on the head (hemorrhage vasogenic oedema)
2. Increased ICP causes the CSF to go into the Spinal cavity (Monro-Kellie Hypothesis)
3. Increased ICP causes more Ischemia, Hypoxia, Hypercapnia causes cerebral vasodilation
4. Goes into the first step of cousin’s triad. Sympathetic nervous system activates causing Peripheral vasoconstriction to increase MAP
5. Baroreceptors in the aortic arch sense the hypertension stimulating the vagus nerve and the parasympathetic nervous system causing bradycardia
6. As pressure continues to increase in the brain putting more pressure on the brain stem this causes irregular breathing.
7. Release of Excitotoxicity neurotransmitters e.g. calcium
8. Neuronal death

Question 26

What is the equation for CPP (cerebral perfusion pressure)

Answer 26

MAP - ICP = CPP

Question 27

How to you work out MAP

Answer 27

BP = HR x TPR