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1 PY1000 > Case study 3 (stroke) > Flashcards

Case study 3 (stroke) Flashcards

1
Q

When does a stroke occur?

A

A stroke occurs when blood circulation to a brain area is blocked and brain tissue dies of ischemia (inadequate blood supply)

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2
Q

Name and describe the most common cause of a stroke

A

Ischaemic stroke; a blood clot blocks a cerebral artery, such as the middle cerebral

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3
Q

Give another name for a stroke

A

Cerebrovascular accident (CVA)

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4
Q

What are TIA’s?

A

Transient Ischemic Attacks (TIA)
“small strokes”
They last for 5 to 50 minutes and warn of impending, more serious CVA’s.
Occur when the brain’s blood supply is interrupted for a very brief time.

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5
Q

Why would the patient have weakness on her left side?

A

A stroke in the right hemisphere will show deficits on the left side of the body

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6
Q

How do strokes cause paralysis?

A

Strokes cause paralysis as the dead part of the brain is unable to send messages to the muscles

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7
Q

What are 3 roles of blood

A 
Transport
 - O2, metabolic waste products
Regulation
 - body temp, pH
Protection
 - prevent blood loss by clotting
 - prevent infection
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8
Q

What are the main components of blood?

A
  • Plasma
  • Red blood cells
  • White blood cells
  • Platelets
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9
Q

What are the walls of the heart called?

A

Epicardium - outer layer
Myocardium - middle layer of cardiac muscle
Endocardium - inner most layer

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10
Q

Describe the myocardium layer of the wall of the heart

A

The thickest layer of the wall of the heart

This is the layer that contracts and is composed of cardiac muscle fibers

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11
Q

Why are the atria walls smaller than the ventricle walls?

A

Atria only have to pump blood into the adjoining ventricles. Ventricles pump blood to the lungs and body.

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12
Q

What is the main role of valves in the heart?

A

Ensure blood flow in one direction - stop backflow

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13
Q

Name the valves in the heart

A 
Atrioventricular valves
 - tricuspid valve (Right)
 - bicuspid valve (Left)
Semilunar valves
 - pulmonary valve (Right)
 - aortic valve (Left)
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14
Q

Describe blood flow through the right side of the heart

A

Pulmonary circulation
R atrium receives deoxygenated blood from the body via superior and inferior vena cava
Blood passes through tricuspid valve into the R ventricle
Then passes through the pulmonary valve into the pulmonary artery
Destination = lungs

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15
Q

Describe blood flow through the left side of the heart

A

Systematic circulation
L atrium receives oxygenated blood from the lungs, via pulmonary veins
Blood then passes through the bicuspid valve into the L ventricle
Through the aortic valve into the aorta
Destination = body

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16
Q

What are the 3 stages of the cardiac cycle?

A

Diastole
Atrial systole
Ventricular systole

17
Q

What do the “lub-dup” sound of the heart represent?

A 
Lub = sound of AV valves closing
Dup = sound of SL valves closing
18
Q

Briefly describe an ECG

A
  • Small rise at start (P) at 0 seconds results from movement of the depolarization wave from SA node through the atria
  • Small dip down, big rise and bigger dip (QRS) at 0.2 seconds results from ventricular depolarization
  • Big rise (T) at 0.4 seconds caused by ventricular repolarization
19
Q

How does smoking increase the risk of a stroke?

A

Carbon monoxide reduces the amount of oxygen in your blood, and the nicotine makes your heart beat faster and raises your blood pressure.
These factors increase smokers’ risk of developing atherosclerosis, a condition where arteries become narrowed and harden. This reduces the blood flow and
makes blood clots more likely to form.

20
Q

Name and describe the second, less common cause of a stroke?

A

Haemorrhagic stroke
Caused by bleeding in or around the brain.
It may be caused when:
• a blood vessel bursts within the brain
• a blood vessel on the surface of the brain bursts, causing bleeding into the area between the brain and the skull

21
Q

What part of the brain is responsible for balance?

A

The cerebellum;

it controls balance, movement, and coordination

22
Q

Give some factors that can increase the risk of a stroke occurring

A
  • smoking
  • high blood pressure (hypertension)
  • obesity
  • age: every decade past 55, the risk of stroke doubles. Approx 65% of strokes occur in those aged 65 and over
  • race: South Asian, African, and Caribbean are most at risk
  • family history: if a close relative has had a stroke, your risk will be higher.
23
Q

What are the key factors a physio should work on with the patient?

A
  • endurance and strength training.
  • core stability
  • exercises incorporating balance, weight-shifting and gait improve balance after stroke.
24
Q

Explain what myotomes are and which would have been affected in this stroke (unable to move her left arm at all and her left leg is weaker than normal)

A

Muscles innervated by nerves related to a particular segment of the spinal cord
C5-C7 = deltoid, bicep, tricep
L2-L4 = illiopsoas, quads

25
Q

Describe the structure of a neuron

A

Nucleus sits in the cell body, with dendrites and an axon extending from. Schwann’s cells are surrounded by a myelin sheath and between these sit the node of Ranvier. Axon terminals are at the end.

26
Q

Briefly describe how an action potential is made

A

The threshold in axon terminal is reached, opening Na+ channels
Na+ enters the hillock, increasing the resting membrane potential
Na+ channels close and K+ channels open
K+ leaves the hillock, making the membrane potential more negative
Potential overshoots and the cell is hyperpolarised
K+ channels close and the cell returns to its resting potential

27
Q

What factors affect speed of propagation and how

A

(conduction velocity)

  1. diameter of axon
    - larger diameter = faster conduction
  2. presence of myelin
    - concentrates Na+ and K+ channels in nodes, increasing conduction velocity
28
Q

What is the central nervous system composed of?

A
  • brain

- spinal cord

29
Q

Give an overview of how an action potential causes contraction of muscles

A

Motor neuron fires an AP down its axon
The axon terminal releases Ach into the synaptic cleft
Ach binds to the receptors on the junctional folds of the sarcolemma.
Ach binding causes a local depolarization called an end plate potential (EPP)
EPP triggers AP in adjacent sarcolemma
Sarcoplasmic reticulum releases Ca2+
Ca2+ binds to tropinin, which shifts tropomysoin to uncover the myosin-binding sites on actin.
Mysoin heads bind to actin
Contraction occurs via cross bridge cycle

30
Q

What are signs of a stroke?

A

Face drooped
Arms weak
Speech slurred
Time to call 999

31
Q

What are some of the most common causes of a stroke?

A
  • hypertension (high blood pressure)
  • artherosclerosis
  • heart disease
32
Q

What is responsible for the regulation of the heart and where is it found?

A

Cardiac control centre is located in the medulla oblongata in the brainstem

1 PY1000 (17 decks)

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