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BL Sem 1 > Lecture 1 & 2 - Homeostasis & Cells > Flashcards

Lecture 1 & 2 - Homeostasis & Cells Flashcards

1
Q

At what temperature would patients with sever hypothermia (<32) start to wake up?
And how are they treated?

A
  • 32 C
  • Full functioning not restored until: 35.5 C
  • Treated with external warming and introduction to warm oxygen + internal fluids
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2
Q

What is the endpoint clinical complication of hypothermia?

A
  • Cardiac arrest. Low body temp can cause the heart to stop beating.
  • Coma is complication of hyperthermia.
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3
Q

What is normal pH of venous and arterial blood?

A
  • Venous: pH 7.35, Arterial: 7.45
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4
Q

70kg man lost 500ml of blood. What percentage of his normal circulating volume of blood has he lost?

A
  • 70kg: 5L of blood

- 500/5000= 10%

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5
Q

Which histological technique is most likely to be used to identify the presence or absence of a tumor?

A
  • H&E staining: Can identify type of cell well
  • SEM, TEM & Confocal microscopy are too ex and produce too much detail for routine investigation
  • Immunohistochemistry: used for prognosis (likely course) of disease one the tumour is indentified
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6
Q

State steps for preparing H&E slides

FECSM

A
  1. Fixation using formaldehyde
  2. Embedding using paraffin wax
  3. Cutting using microtome
  4. Staining
  5. Mounting
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7
Q

Which histological procedure uses ultrathin sections of embedded tissue that are cut with glass or diamond?

A

TEM

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8
Q

Which technique should be used to identify and localise a specific protein in the cell nucleus?

A
  • Immunohistochemistry: antibody would be specific to the target protein
  • SEM, TEM, Freeze Fracture X: Used for general detection for cellular ultrastructure
  • Routine H&E: Non-specific + detects most cellular structures
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9
Q

State temperature range & symptoms for fever (1), heat stroke (2) and heat exhaustion (3).

A
  1. > 38.5C: pale sweaty skin, cramps in arms and legs
  2. 40- 46: Flushed dry skin, hot to touch, strong bounding pulse
  3. > 46: Unconsciousness, seizures, confused, dizzy, coma
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10
Q

State temperature range & symptoms for mild hypothermia (1), severe hypothermia (2) and no vital signs (3).

*Not dead until WARM & DEAD

A
  1. 32–35C: Shivering, fatigue, slurred speech, confusion
  2. <28: Shivering stops, muscles become rigid, very slow and weak pulse, drowsiness, reduction in response levels
  3. Same range?: Unconsciousness, dilated pupils, pulse undetectable
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11
Q

What is normal pH?

A
  • pH 7.35- 7.45
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12
Q

What are the pH limits to human tissue survival?

A
  • pH 6.8-7.8
  • When pH = 7.3, [H+] = 50, so if pH =7.0, [H+] = 100
  • pH change either doubles of halves [H+]
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13
Q

State some buffering systems in the body.

A
  • Bicarbonate (erythrocytes as intermediary)
  • Sodium phosphate

Drugs:
- AI(OH)3 mildly alkaline, insoluble: good acid neutraliser (control heartburn)

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14
Q

Body Fluid Compartments for 70kg male

A 
- 70kg: 40% solids, 60% liquids
 Liquid:
1. 70 x 0.6 = 42 kg
2. 2/3 intracellular, 1/3 extra
3. Of the 1/3 extra: 0.75 is interstitial fluid, 0.25 is plasma
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15
Q

Who has the highest total body water?

A
  • Infants have the highest percentage of TBW, followed by adult male then female
  • The higher % of body fat the lower the TBW

*the older you get, the less TBW

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16
Q

What happens when there’s not enough H2O?

A
  • Cells and tissues initially absorb water from interstitial space
  • Then each other –> organs –> brain, liver, kidney, heart
17
Q

Define osmolality

A
  • Conc of solute particles per kg in sol.
  • For glucose/urea, osmotic pressure is no. of mmol present= 1mOsmol
  • For ions, NaCI= 2mOsmol
18
Q

What causes oedema? Symptoms of oedema.

A
  • Oedema is fluid retention. Swollen ankles.
  • Hydrostatic pressure > Osmotic pressure
  • More H20 driven out to I.S
19
Q

What are the disadvantages and advantages of formalin fixation?

A

A: - Can be preserved for very long peroid
- Produce many slides
D: - Long prep. time
- Unable to see lipid-containing structures

20
Q

What are the advantages and disadvantages of frozen section?

A

A:- Short prep time (20 mins)
- Preserve lipid-containing structures
D: - Not clear. Presence of ice crystals produce blurry images

21
Q

What is the definition of homeostasis? What needs to be maintained in human body?

A
  • Maintenance of a relatively constant internal enviro.
  • Conc. of O2,CO2, pH, Temp, BG
  • Use of (+)/(–) feedback loops
22
Q

What occurs when body temp ⬆️ and when body temp ⬇️?

A
  • Thermoreceptors in hypothalamus detect change,

When ⬆️,

  • Vasodilation: Increase heat loss from capillaries near surface of skin
  • Sweating: Reduce body temp
  • Pilorelaxation: Hairs flatten
  • Stretching out: Larger SA

When ⬇️,

  • Vasconstriction: Less heat loss from skin surface
  • Shivering: Rapid contraction of skeletal muscles
  • Piloerection: Hairs contract, trap layer of air
  • Curling up: Reduce SA
23
Q

Why is Al(OH)3 a good antacid?

A
  • Midly alkaline
  • Insol. = good acid neutraliser, increase pH
  • Can control heartburn
24
Q

What happens when there is X enough water?

A
  • Cells and tissues initially absorb water from interstitial space –> each other –> organs –> brain, liver, kidney, heart
25
Q

What happens if there is too much water? How to prevent this in IVF of patient?

A
  • Osmotic pressure ⬆️–> cells absorb water and swell –> enzymes & proteins X work –> cell burst
  • To prevent use isotonic solutions, 0.9% saline (NaCI)
26
Q

Define tissue and state its 4 types

A
  • Group of cells that have similar structure and function together as a unit.
  • Epithelial, Muscle, Connective, Nervous
27
Q

What are the advantages of using SEM and TEM?

A
  • SEM: Visualise surface of cell

- TEM: Examine intracellular structure and organelles

28
Q

What are some common biopsy techniques?

A
  • Curettage (endometrium tissue)

- Venepuncture

29
Q

Stain diff. type of stains and what they stain

A
  • Haematoxylin: acidic stuff, DNA & RNA [blue]
  • Eosin: alkaline, protein [red]
  • Masson’s trichome: Red (keratine, muscle fibres), Blue/green (collagen, bone), Pink (cytoplasm)
  • Periodic Acid-Schiff stain: sugar
30
Q

Desc. immunohistochemistry. What is antigen retrival?

A
  • Enzyme activated secondary antibody complexes = indirect immunohistochemistry
    (peroxidase- brown, acid phosphatase- colourless)
  • Antigen retrieval: partial digestion of ‘fixed’ proteins by heating tissue w weak acids (done bcs some targeted antigens structure change after fixation)
31
Q

What is dark field? What is it use on and how?

A
  • Used w living cells
  • Illuminate sample w light –> dark appearance w bright objects on it
  • Used w electron microscopy
32
Q

What are some treatments that utilise hypothermia or hyperthermia?

A
  • Hypo: Used on patients after cardiac arrest/stroke –> divert blood to vital organs
  • Hyper: Damage/Kill cancer cells w little/X harm to other cells (increase temp. of tumour, ⬆️blood flow & oxygenation = more sensitive to radiation)
33
Q

Why is an undescended testis a problem?

A
  • Core body temp too high for sperm production–> infertility
  • Cancer risk –> testicular (seminoma)
    [temp ⬆️, cells replicate faster]
  • Testicular torsion: testis twists around each other –> cut off blood supply –> necrosis
34
Q

To treat fever a patient is given paracetamol, is that a good idea?

A
  • Paracetamol reduces fever by affecting chem. messenger in hypo. that regulate temp
  • Good: Reduces fever & help pain relief
  • Bad: Immune system work harder, infection longer
35
Q

Define pyrexia. Why does it occur?

A
  • Body temp ≥38.5C
  • Increase immune system efficacy by increasing temp to denature enzymes in bac.
  • Upon infection, IL6/IL1 increases temp. setpoint
36
Q

What is rigor? When does it occur and why?

A
  • Sudden feeling of chill/shivering due to ⬆️temp

- Common in fever, psychological response to increase setpoint

37
Q

What is a febrile seizure and how does it differ to rigor?

A
  • Fits when child has a fever, unknown cause

- Febrile convulsions caused by rapid changes in temp (not fever), rarely harmful

38
Q

Symptoms of adult, baby and elderly being dehydrated are…

A
  1. Adult: dry mouth, dizzy, drowsy
  2. Baby: Dry lips, sunken eyes, dry skin
  3. Elderly: Dry lips, dry skin, drowsy
39
Q

What happens when you drink too much water. Symptoms?

A
  • If drink too quickly, cells take up too quickly and swell–> oedema
  • Brain cells swell –> convulsions –> coma/death
  • Symptoms: seizure, confusion, nausea, headaches

BL Sem 1 (13 decks)

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