Pre ICA - Nerissa Flashcards
What is the difference between eukaryotes and prokaryotes?
Eukaryote - multicellular, diploid, and has nucleus.
Prokaryote - Unicellular, haploid, and does not have a nucleus.
What are stem cells?
Unspecialised cells, that divide and differentiate to become somatic cells.
What is the plasma membrane commonly known as?
The security of the cell.
What happens when there is increased permeability?
Ca influx, which activates membrane repair response.
What happens if membrane repair response is over-activated?
Cancer invasion.
What happens if the membrane repair response is under-activated?
Neurodegeneration and muscular dystrophy.
What is a membrane made out of?
Lipids.
What happens if configurations of lipids are altered?
Causes increase in membrane permeability. The function of the membrane is lost.
What happens when membrane function is lost?
Membrane becomes vulnerable, neurodegenerative diseases.
Myocardial infarction results into what?
ischemia - damages the membrane, which cause an increase in permeability.
What happens when there is an increase in membrane permeability due to ischemia?
Influx of ions and fluids, this make the cell small, forming blebs
What are glycocalyx?
Glucose chains that are attached to lipids and proteins
What is the function of glycocalyx?
Cell recognition.
Cell-to-cell interaction.
What happens if CFTR is either faulty or absent?
Cystic fibrosis. Water cannot hydrate cellular surface, chloride trapped in cell.
What is brugada syndrome?
SCN5A Na cardiac channels mutations. Decrease in Na causes abnormal heartbeats.
If someone comes down with a fever, what happens to the fluidity and rigidity of the membrane?
Less rigidity and more fluidity.
Proteins and molecules go in and out, which can change the permeability - allowing harmful molecules to enter.
What is kartagener’s syndrome?
Autosomal recessive. Microtubule.
Impaired mucociliary clearance.
Immobility of sperm tail.
Impaired ciliary action of ovum.
What is Alzheimer’s disease?
Defective changes in neurofilaments. Intermediate filament.
Produces tangles and aggregations.
What is nucleoplasm?
Surrounds chromatin and nucleoli. Transcription (DNA -> RNA).
What is the nucleolus?
RNA synthesis and ribosome assembley.
What is Euchromatin?
Active transcription.
What is heterochromatin?
Inactive transcription.
What is Emery-Dreifuss muscular dystrophy?
Affects adipose tissue, skeletal muscle, peripheral nerve or skeletal development.
What is Laminopathies?
Mutated gene that is encoding lamina.
What cells are devoid of a nucleus?
Keratinocytes and RBC’s.
What is rough endoplasmic reticulum?
Increased protein secretion - pancreatic acinar cells, fibroblasts and plasma cells.
Modification and folding of proteins synthesized on ribosomes.
What is smooth endoplasmic reticulum?
Cells that secrete steroid hormones - adrenal cortex, testis and ovaries.
Synthesis of lipids.
What is neonatal jaundice?
Underdeveloped smooth endoplasmic reticulum in liver cells. Error in bilirubin metabolism.
What is hurler syndrome?
lack of an enzyme that the body needs to digest carbohydrates.
What is gaucher disease?
Fat-laden gaucher cells build up in places like spleen.
What is Tay-sachs disease?
Absence of enzyme that breaks down fatty substances.
What are the effects of drugs on lyosomal function? Chloroquine accumulation.
Increase pH of lyosomal content.
Inactivated lyosomal enzymes.
Inhibits autophagy but activates apoptosis.
What is the shape of cells in the distended and non-distended transitional epithelium?
Non-distended: Base is cuboidal, middle is polygonal, surface is dome shaped.
Distended; Base is cuboidal, while the middle and surface are flat.
What are facultative dividers?
Go — May re-enter cell if needed. Fibroblasts, hepatocytes, pancreas, kidney, and breast.
What is the G1 phase?
Longest phase - active RNA and protein synthesis.
What happens in the G2 phase?
Cells prepare for mitosis.
What is GTD?
When cells lose the ability to undergo mitosis - point of no return. Cardiomyocytes, neurons.
What is static cell population?
Cells that no longer divide - found in skeletal and cardiac muscle.
What is stable cell population?
Cells that divide slowly to maintain normal tissue structures - found in smooth muscle cells, fibroblasts and perichondral cells.
What is renewing cell population?
Slowly or rapidly but with normal mitatic activity. Rapidly - blood cells
Slowly - smooth muscle cells of hollow organs.
What is the G1 DNA-damage checkpoint?
Monitors quality of newly formed cells. Target in cancer cells.
What are the most important checkpoints in the cell cycle?
Between G1 and S- restriction checkpoint.
What happens in the restriction checkpoint?
Cell evaluates it ability to replicate - No way of returning.
What happens in unreplicated DNA checkpoint?
If DNA synthesis is not complete, it will prevent progression of cell into M phase.
What does the cell cycle require?
Cyclin and Cyclin-dependent kinase.
Where is CyclinD-CDK4/6 found?
In G1.
If there is mutation in the G1 phase (cdk) what would happen?
Primary microcephaly
What are proto-oncogenes?
Timing of cell division.
What are tumor suppressor genes?
Suppress abnormal cell growth.
What happens if there is a mutation in the G1 & S & G2 checkpoints?
Failure to arrest cycle - Abnormal chromosome segregation.
What is used for cancer therapy?
S & G2.
What is asynopsis?
Mutations in encoding genes for synapses.
Meiotic recombination defects.
Apoptosis in gametes - infertility.
What is necrosis of cell?
Impairment of cell’s ability to maintain homeostasis- cause by acute cell injury.
What is apoptosis?
Normal - controlled autodigestion.
What happens when cell death is higher than cell division?
Net loss will occur - AIDS, Alzheimer’s, Parkinson’s and myocardial infarction.
What happens when cell division is higher that cell death?
Net gain increases - Cancer, lupus, and viral infections.
What are examples of simple squamous epithelium?
Endothelium - diffusion and exchange.
Alveoli of lung - diffusion and exchange.
Mesothelium - facilitates movement wishing body cavity.
What are examples of simple cuboidal epithelium?
Tubules of kidney - filters blood through absorption.
Ovary - repair.
Thyroid gland - secretion of hormone.
Bile duct of liver - secretion of bile.
What are examples of non-ciliated simple columnar epithelium?
Stomach - digestion.
Gall bladder - absorption.
Colon - absorption.
What are examples of ciliated simple columnar epithelium?
Fallopian tubes - secretory and transport.
What are examples of non-keratinized stratified squamous epithelium?
Oral cavity, pharynx, osophagus, vagina - protection.
What are examples of keratinized stratified squamous epithelium?
Epidermis, anus - protection.
Differentiate between stratified cuboidal and columnar epithelia?
Stratified cuboidal - 2-3 layers, ducts of salivary glands and minimal secretion.
Stratified columnar - basal cuboidal cells + superficial columnar cells, ducts of exocrine glands, male urethra and palpebral conjuctiva, secretion and protection.
What are examples of non-ciliated pseudostratified columnar epithelium?
Vas deferens and epididymis - absorption. No goblet cells
What are examples of ciliated pseudostratified columnar epithelium?
Upper respiratory tract - secretion.
What happens with habitual smokers with chronic bronchitis?
Increase in goblet cells, excess mucus production in areas of limited cilia.
Differentiate between non-distended and distended transitional epithelium?
Non-distended - scalloped, 4-5 cell layers.
Distended - flattened, 2-3 cell layers.
What happens when there is squamous metaplasia in bronchi?
Ciliated pseudostratified columnar epithelia gets replaced by stratified squamous epithelia. increased risk of dysplasia and carcinoma.
What happens in barrett’s esophagus? epithelial metaplasia.
Chronic GERD - stratified squamous epithelia gets replaced by simple columnar with goblet cells. May progress to adenocarcinoma.
What is the main protein in the tight junction?
Occludins.
What is a tight junction?
Prevents molecules from going to adjacent cells.
What is the main protein in adhering junction?
Cadherins.
What is a adhering junction?
Maintain cellular position.
What is the main protein in a Gap junction?
Connexins.
What is a gap junction?
Acts as channels - passage of ions and molecules.
What is the main protein in a hemidesmosome?
Integrins laminins.
What is a hemidesmosome?
Anchors and connects cell to lamina.
What happens in food poisoning?
Chlostridium perfringens attacks tight junction. Leads to malfunction to that junction.
What happens in an asthma attack?
Dust mites and pathogens attack tight junction.
Give characteristics of serous and mucus cells.
Serous - Small pyramidal, large ducts, and round-centred nucleus. Dark staining and enzymatic action.
Mucus - short columnar, small ducts, and flat nucleus. Light staining and protection and lubrication.
Where is a simple tubular gland found?
Colon - secretion.
Where is a simple coiled tubular gland found?
Sweat glands - secretion (merocrine).
Where is a simple branched tubular gland found?
Stomach and intestine - secretion (mucus secreting cells).
Where is a simple acinar gland found?
Penile urethra - mucus-secreting cells.
Where is a simple branched acinar gland found?
Sebaceous glands - serous-secreting cells.
What are sebaceous glands involved in?
Acne vulgaris.
What is acne vulgaris?
Excessive holocrine secretion of sebum and keratin.
Blockage of glandular ducts.
Compound branched tubular glands can be found where?
Brunners glands of duodenum - mucus-secreting cells.
Where can compound acinar glands be found?
Pancreas has number of acini and mammary glands - serous-secreting cells.
Where can compound tubulo-acinar glands be found?
Salivary glands - mucus-serous cells - merocrine secretion.
Where does cell exfoliation occur?
Skin epidermis.
Surfaces of internal cavities.
Major exocrine ducts.
What are muscle tissue properties?
Excitability.
Extensibility.
Elasticity.
Contractility.
What are characteristics of skeletal muscle cells?
Function - protection.
Nuclei - multinucleated.
Voluntary movement.
Well developed sER and T tubules.
What are the structural components from outer to middle?
Epimysium.
Perimysium.
Endomysium.
Myocyte.
Myofibril.
Myofilament.
What is sarcolemma?
Myocyte cell membrane.
What is sarcoplasm?
Cytoplasm of myocyte.
What is sarcoplasmic reticulum?
form of ER, houses intercellular Ca.
What is a triad in myocyte?
2 terminal cisternae + T tubule.
What does the I band contain?
Myofilament actin.
What does the A band contain?
Myofilament myosin.
What does the H zone contain?
Myosin.
What does the Z disc contain?
Actin.
What is actinin?
Structural - attaches actin to Z-disc.
What is tintin?
Elastic - Stabilize position of myosin.
What is dystrophin?
Cohesive - links thin filaments to sarcolemma.
What happens in a relaxed state?
Tropomyosin blocks actin-myosin binding site.
What happens during contraction?
SR releases Ca.
Ca binds to troponin.
Troponin moves tropomyosin out of the way.
Actin-myosin binding happens.
Where would we find Fast-twitch type IIB?
Extraocular and limb digits.
Where would we find Fast-twitch type IIA?
Major lower limb muscle.
Where would we find Slow-twitch type I?
Postural muscles.
What are signs of myasthenia gravis?
ptopia, dysphagia, diplopia.
What are characteristics of cardiac muscle cells?
Involuntary.
Joined at intercalated discs.
Centrally - Located nuclei.
What is a diad in cardiac muscle cell?
1 T tubule + 1 End of SR.
What is a transverse component of the intercalated discs?
Perpendicular to myofibrils.
Desmosome: reinforce fascia and cell-cell adhesion.
Fascia adherens: attachment site for I bands.
What is a lateral component of the intercalated discs?
Parallel to myofibrils.
Gap junctions: passage of macromolecules and electrical impulse.
What happens when there is occlusion of coronary artery?
Reduce blood supply, ischemia - myocardial infarction. Lack of satellite means cannot regenerate, replacement with fibrous tissue.
What is the difference between diad and triad?
Triad - complex, AI junction, 2.
Diad - simpler, Z disc, 1.
What are some characteristic of smooth muscle cells?
Walls of hollow organs, well developes sER, involuntary.
What is multi-unit smooth muscle?
Not electrically connected, iris of eye and epididymis.
What is a single-unit smooth muscle?
Electrically connected, visceral smooth muscle of hollow organs.
What is leiomyomas?
Tumour of smooth muscle.
Occurs in uterus.
What are causes of leiomyomas?
Hormonal changes.
Family history.
Pregnancy.
