BF Exam Questions Flashcards
- describe the structure of the plasma membrane
phospholipid bilayer- 2 layers of phospholipids tightly held
phospholipid = phosphate head (hydrophilic + electrically charged)and 2 lipid tails (hydrophobic + not electrically charged) Within the PM, there are also carbohydrates that help with recognition, and proteins (help transport substances across the PM) and cholesterol that helps support semi-permeability
separates two fluid compartments
- briefly outline difference between mitosis / meiosis
mitosis
- occurs in all body cells except sex cell (ova and spermatozoa)
- used to to replace damaged / worn out cells + support growth
- 1 stage process whereby cell replicates into 2 identical daugther cells (each with identical 23pairs of chromosomes = 46 chromosomes)
meiosis
- occurs only in sex cells
- 2 stage process whereby cell divide once to create 2 daughter cells (Each with 46 chromosomes), than again to create 4 daughter cells - each genetically unique and with only 23 chromosomes
- what is difference between RER and SER
Rough endoplasmic reticulum (ER):
covered in ribosomes Manufactures extracellular proteins, membrane proteins and phospholipids
Smooth endoplasmic reticulum:
no ribosomes
Lipid metabolism
Synthesis of steroid hormones
Absorption, synthesis & transportation of fats (in intestinal cells)
Detoxification of drugs and other toxins (in liver and kidney cells)
Breakdown of stored glucose (glycogen)
2.outline structure and function of epithelial tissue- provide example
- Covers body surfaces, lines body cavities and forms glands
- Forms a boundary between different environments
- classified by shape (cuboidal, columnar, squamous) + layers (stratified, simple)
- Functions: Protection Absorption Filtration Excretion Secretion e.g. lungs- filtration - skin- secretion GI tract- absorption
- special characteristics
- joined by tight junctions
- supported by connective tissue (basememnt membrane)
- avascular (don’t have own blood cell, receive nutrients diffused from underlying CT)
- has nervous innervation
- high capacity for regeneration
- Define types of Connective Tissue
-
Loose CT
- Areolar
- Adispose
-
Dense CT
- Regular
- Elastic
- Cartilage
- Bone (Osteocytes + Fibre + Ground Substance (calcium and phosphorus)
- blood
- Define membranes and three types
- ine body cavities and cover body organs
- composed of both epithelium and connective tissue proper (adipose + areolar)
Three types:
- Cutaneous membrane: skin (integument)
- Mucous membranes: secrete mucus and line body cavities that open to the exterior (e.g. digestive, urinary, respiratory tracts)
-
Serous membranes: double-layered membranes that line closed (internal) body cavities and cover organs
- Parietal layer: lines a body cavity
- Visceral layer: covers viscera (body organs)
- Serous fluid between the 2 layers
- Define 4 types of regenerative capability and identify the tissues
High regenerative capabilities - epithelium / bone / areolar CT/ blood
Moderate regenerative capabilities- smooth muscle / dense regular CT
Weak Regenerative capabilities - Skeletal muscle / cartilage
Limited regenerative capabilities - Cardiac muscle / nervous tissue
Describe process of tissue repair
3 steps
- Inflammation- goal is to quickly form clot and get infection avoided
- damaged cells (and other cells) release inflammatory chemicals which
- make capillaries dilate enabling more blood flow to injured site (red and inflamed appearance
- increased capillary permeability-WBCs and clotting agents go to damaged tissu
- stimulate pain receptors to create conscious awareness of damaged tissue
- clot forms- seals off injured area (To prevent bacteria etc from spreading) and prevents further blood loss
- WBC’s help clean up debris and fight / prevent infection at site
- Organisation
- Clot is replaced by Granulation Tissue- fragile capillaries that restore blood supply
- firbroblasts multiply and produce growth factors (wound hormones) and collagen fibres that bridge gap from wound
- macrophage digests clot
- surface epithelial cells start muptiplying and begin to migrate over granulation tissue
- Regeneration / Fibrosis - replaced damaged tissue
- if there are sufficient uninjured cells near injury site, these undergo cell division to regenerate new cells and then migrate to injury site
- if there aren’t enough cells to regenerate or damage is too severe, injured tissue may be replaced by fibrous tissue forming scar tissue
- Non-damaged cells around injured site start cell replication (mitosis) and then migrate to injured site and replaced damaged cells.
- If there are not enough cells / too much damage, dense CT (fibrous tissue) used instead- forming scar tissue
Describe Neg feedback with an example
Inhibitory system , whereby the Effector acts to reverse/ eliminate change in controlled condition (Stimulus) to align with Set point of hypothalamus example- thermoregulation 1) Receptors- thermoreceptors in skin detect external environment temperature decrease- send info to CC 2) CC- hypothalamus reviews info against set point and makes stimulates Effector to respond 3) Skeletal muscle- shivering / vasoconstriction (Reduce blood to outer skin surface / put on clothes)
describe positive feedback with an example
- Stimulatory Response system amplifies / enhances original Stimulus, moving Controlled condition further away from normal
- e.g. childbirth
- normally, strech receptors in pelvis don’t have any pressure, however during childbirth they get stimulated
- Stimulus- baby descends into pelvis, putting pressure on stretch receptors receptor-
- stretch Receptor in pelvis detect pressure from descending newborn and send info to CC
- CC (hypothalamus)- review input from CC against baseline (no pressure on stretch receptors) and stimulate Effector to respond via hormones (oxytocin)
- Effectors - smooth muscle in uterus stimulated to contract, increasiing the stretch of the cervix until fully dilated, allowing baby to move further down and place more pressue on stretch receptors. Cycle continues until baby is born, and pressure on stretch receptors ceases, and certvix returns to normal homeostatic state of no stretch/dilation
