Pathology of Wound Healing
What is an example of a labile cell?
Epidermis of skin, bone marrow and mucous membranes
Name 2 antagonist muscles in the upper arm
Biceps brachii and Triceps brachii
Define nociception
Stimulation of the nociceptors by noxious stimuli (mechanical, chemical, thermal etc.) which signals the brain to indicate actual or potential damage
What triggers the exocytosis of synaptic vesicle contents?
Calcium entering the cell due to depolarisation
What are the two primary tests for the emergency management of Acute Coronary Syndrome?
ECG and Troponin I
What phase of the cell cycle do stable cells reside in?
What phase do they enter when they proliferate?
G0
G1
What is the region of the sarcomere that has only myosin
H-zone
What is the rate of healing for an axon in the PNS?
1-4mm/day
What are the brain waves in order of increasing frequency?
Delta, Theta, Alpha, Beta, Gamma
What is the landmark for locating the dorsalis pedis pulse?
It lies laterally to the extensor hallicus longus
What are the two steps of wound repair?
1. Formation of the granulation tissue
2. wound contraction - myofibroblastic activity
What is the recurring unit of the myofibril termed as?
The sarcomere
What was the test we did on Tony to test his nerve integrity?
Tinel's Test
What are the 4 fates of neutotransmitters entering the synaptic cleft?
1. Bind with the post synaptic receptor
2. Inactivated by neurotransmitters
3. Re-uptaken into the presynaptic cell or the glial cell
4. Diffuse out of the synaptic cleft
What is the primary bacterial pathogen causing epiglottitis in childrens and adults?
Children - Haemophilus influenzae type b
Adults - Strep pneumoniae or group A strep
What are the 4 steps of cutaneous wound healing
1. Haemostasis
2. Inflammation
3. Proliferation
4. Remodelling/maturation
How does an action potential travel from the neuromuscular junction to reach the cytoplasm of the muscle? What is it's next action once it reaches the cytoplasm?
Travels down the T-tubules of the sarcolemma
It's entrance in the cytoplasm causes the opening of calcium channels in the sarcoplasmic reticulum
In an axonotmesis injury, what would be the damage to the endoneurium, axon and myelin?
How do you recover?
Endoneurium - none
Axon - damaged
Myelin - moderate demyelination
Recovery is entirely spontaneous
What are 3 changes that occur during REM sleep?
1. Darting of the eyes
2. BP and HR increase
3. Skeletal muscle paralysis
4. Brain shifts to the highly active state
5. Dreams occur at this stage
ABG: pH 7.25
pO2 72.7
CO2 29.7
HCO3- 14.9
K+ 4.6
Na+ 140
Lac 11.5
Hb 122
Give a detailed report on the ABG
Metabolic acidosis with partial compensation
Patient is also hypoxaemic (mild)
Increased lactate only other abnormality
What are 4 SYSTEMIC factors that affect wound healing and an example of each
Nutrition - protein deficiency/vitamin C
Metabolic status - diabetes
Circulatory status - venous abnormalities
Hormones - glucocorticoids
Explain the 4 steps of the "power stroke"
1. ATP binds to myosin and myosin releases actin
2. Myosin hydrolyzes ATP. Energy from ATP rotates the myosin to the cocked position. Myosin now binds weakly to actin
3. Power stroke begins when tropomyosin moves off the site as calcium binds to troponin
4. Myosin releases ADP at the end of the power stroke
Explain Wallerian degeneration from injury until end point
1. Injury (the cut)
The axon is severed, separating it into a proximal segment (still attached to the cell body) and a distal segment (cut off from the cell body).
2. Changes in the cell body (proximal side)
The neuron's cell body reacts to injury — Nissl substance disperses and aggregates, a sign the cell is shifting into a "repair" metabolic state.
3. Degeneration of the distal segment
Cut off from the cell body's support, the distal axon segment begins to break down — this starts within about a week and can continue for 1–2 months.
4. Breakdown of axon and myelin
The axon fragments, and the myelin sheath surrounding it degrades and is lost, leaving debris (axonal and myelin fragments) in the distal stump.
5. Glial cell invasion
Glial cells (including Schwann cells) migrate into the area and push the remaining synaptic terminal away from the postsynaptic neuron, disconnecting the synapse.
6. Phagocytosis / clearance
Schwann cells (and macrophages) phagocytose (engulf and clear) the axonal and myelin debris, cleaning the site — this clearance is a necessary step before any potential axon regrowth can occur.
What are the 4 stages of non REM sleep
Stage 1: alpha wave activity
Stage 2: Irregular EEG or sleep spindles (short, high amplitude bursts)
Stage 3: Sleep deepens - theta and delta waves increase
Stage 4: Delta waves dominate
Name 5 appropriate lab investigations for a pregnant woman
- Beta HCG
- FBC
- UEC
- HIV/HEP b antigen
- Group and Hold
- Urine MCS