Intro to Med - Phase 1 Flashcards
What are the seven major organelles and their functions?
NUCLEUS – site of DNA transcription + translation
SMOOTH ER – lipid synthesis
ROUGH ER – protein synthesis
MITOCHONDRIA – sites of cellular metabolism, generation of ATP
GOLGI APPARATUS – vesicular packaging/transport
RIBOSOME – site of translation
LYSOSOME – enzymes for degradation of cellular products or pathogens
Layers of the EPIDERMIS- skin (structure and function)
STRATUM CORNEUM
- thick outer layer of dead cells
- physical/chemical barrier
STRATUM LUCIDUM
- thin layer of cells only in thick skin
- strengthening
STRATUM GRANULOSUM
- flattened cells with keratohyalin and lamellar granules, – nuclei disintegrate
- permeability barrier
STRATUM SPINOSUM
- spiny cells with desmosomes, Langerhans cells
- immune function, strength to resist abrasion
STRATUM BASALE
- stem cells, melanocytes, Merkel cells
- generate new keratinocytes, pigment, sense of fine touch
Structure and function of DERMIS and HYPODERMIS
DERMIS important for immune surveillance, thermoregulation
- papillary layer: anchors epidermis, immune cells, fibroblasts
- reticular layer: blood vessels, nerves, lymph
HYPODERMIS: adipocytes for thermoregulation/insulation, energy storage, cushioning
Types of burns (layers, signs/symptoms, management)
SUPERFICIAL:
- epidermis only, hair follicle invaginations allow for regeneration
- pain, heat, erythema, swelling, tenderness
- cold water, pain management
PARTIAL:
Superficial Partial = papillary,
Deep partial = reticular
- some pain insensitivity, blistering
- infection control
FULL THICKNESS:
- all three layers,
- no ability to regenerate due to loss of basal stem cells
- black charring or white from fat necrosis
- skin graft required,
- high risk of infection and dehydration
Define Homeostasis and describe the feedback mechanisms
Homeostasis = the maintenance of a constant internal environment by various physiological processes despite changing conditions
Negative feedback: stable, changes are counteracted with opposite changes to maintain homeostasis
Positive feedback: unstable, changes perpetuate further changes in the same direction
Process of action potential generation
Graded potentials occur due to release of neurotransmitter at the dendrites, summation of GPs at axon hillock leads to depolarisation
- Voltage change triggers opening of VGSCs, rapid Na+ influx depolarises membrane
- Opening of VGPCs due to depolarisation, K+ efflux repolarises → hyperpolarisation
- Na+/K+ ATPase returns membrane to resting potential (-70mV)
Types of hormones (synthesis, receptors, solubility, examples)
PROTEINS
Synthesis: amino acids
Solubility: hydrophilic
Receptor: membrane-bound
Examples: insulin, ACTH
STEROID
Synthesis: cholesterol
Solubility: lipophilic
Receptor: nuclear → forms TF
Examples: cortisol, oestrogen
AMINE
Synthesis: tryptophan/tyrosine
Solubility: varied
Receptor: varied
Examples: adrenaline, T3, T4
Lipid hormones will have longer half-life as protein bound and more prolonged but delayed effect as they require protein synthesis, compared to protein hormones
Composition of bodily fluids (intracellular and extracellular)
ICF – K+, proteins
ECF – Na +, Cl-, HCO3-, plasma proteins
Stages of dehydration
MILD: (4-6%)
- increased thirst
- oral fluids
MODERATE: (7-10%)
- sunken eyes, dry membranes,
- tachycardia, ↓ urination/sweating
- oral or IV fluids
SEVERE: (>10%)
- neurological dysfunction, hypotension, anuria
- oral, IV or interosseous fluids
Causes of dehydration
There are three major categories for causes of dehydration:
- Decreased intake – water scarcity, behavioural problems
- Increased water loss – vomiting, diarrhoea, profuse sweating
- Fluid shift – ascites, pleural effusion
Definitions of tonic vs. osmotic
Tonic = used when comparing a solution to a cell e.g. hypertonic, hypotonic, isotonic
Osmotic = used when comparing two solutions e.g. hyperosmotic, hypoosmotic, isosmotic
Four types of body tissues and their characteristics
Levels of structural organisation for proteins
Primary – polypeptide chain made of a sequence of amino acids
Secondary – α-helices and β-sheets
Tertiary – folding of chains into final protein shape
Quaternary – combination of multiple protein subunits together
Cell adhesion structures
Tight junctions: form barriers to block movement between cells
Desmosomes: anchor cells together with cadherin proteins
Gap junctions: allow flow of ions for intercellular communication
- *Branches of the autonomic nervous system:
- Origin
- Fibre Length
- Ganglia
- Neurotransmitter
- Receptors
- Function**
Types of sweat glands
Merocrine/eccrine = most common, sweating for thermoregulation (SNS via ACh + muscarinic)
Apocrine = located in arm pits and groin, nervous sweating + pheromones
Types of cellular receptors
Mechanisms for membrane transport
FAVS
Facilitated diffusion: pores, channels, carriers (uniporters, symporters, antiporters)
Active transport: primary and secondary
Vesicular transport
Simple diffusion
Social determinants of health
ERASER
Education + Training
Resources availability of food, housing, medication
Access to healthcare, education and economic opportunity
Social support
Employment and socio-economic status
Rurality