IAS19-21,23,29-30,39

Question 1

The embryonic origin of epithelium? Examples of epithelium for each?

Answer 1

Ectoderm: skin epithelium

Mesoderm: endothelium of blood vessels, lymphatics, mesothelium (pericardium, peritoneum, pleura), urogenital system (genital ducts, urinary ducts and tubules)

endoderm: GI tract lining, lining of lower respiratory system

Question 2

Features of epithelial tissues?

Answer 2

1) lie on basement membrane
2) avascular
3) junctional complexes present to form 1 continuous layer
4) presence of cytokeratin for attaching to junctional complexes
5) little or no intracellular matrix

Question 3

Examples of simple squamous epithelium?

Answer 3

Endothelium of blood vessels, mesothelium, respiratory epithelium

Question 4

Example of stratified squamous epithelium (keratinized and non-keratinized)

Answer 4

Keratinized: skin epithelium
non-keratinized: esophagus lining, vaginal lining, buccal cavity lining

Question 5

Example of stratified cuboidal epithelium?

Answer 5

Rare and uncommon type of epithelium: duct of sweat gland

Question 6

Example of simple cuboidal epithelium?

Answer 6

Lining of most ducts, eg pancreatic gland, thyroid gland

Question 7

Example of simple columnar epithelium?

Answer 7

Absorptive lining of small intestine, oviduct (ciliated)

Question 8

Example of stratified columnar epithelium?

Answer 8

Lining of large excretory ducts, anus

Question 9

Example of pseudostratified columnar epithelium?

Answer 9

Lining of trachea, bronchi, epididymis

Question 10

Example of transitional epithelium?

Answer 10

Urinary bladder lining

Question 11

Functions of microvilli and their mechanism for their function?

Answer 11

For absorption of nutrients from intestinal lumen

mechanism of absorption: microvilli have actin core connected to terminal web, when terminal web contracts microvilli can absorb foodstuff

Question 12

Functions of cilia and mechanism of action?

Answer 12

Coordinated unidirectional movement

Question 13

What are junctional complexes composed of?

Answer 13

Tight junction, Adhering junction, desmosome/hemidesmosome

Question 14

Which components of junctional complex are belt like structures and their function?

Answer 14

Tight junction, adhering junctions

functions:
tight junction for sealing, prevent fluid leakage between epithelial cells (vacuum seal)

adhering junction for adhesion between cells (aa glue)

desmosomes: connected to cytokeratin fibers, anchor the cells together to prevent damage when stretched/when tearing forces applied(anchor)

Question 15

Functions of gap junctions?

Answer 15

communication, coordinated muscle contraction

Question 16

Serous meaning?

Answer 16

watery protein-based secretions, basophilic

Question 17

Mucinous meaning?

Answer 17

thick mucin-based secretions, pale stain

Question 18

Merocrine vs apocrine vs holocrine?

Answer 18

Merocrine: exocytosis
apocrine: loss apical (decapitation secretion)
holocrine: lysis of entire secreting unit

Question 19

Locations where mucous membranes are located?

Answer 19

body cavity connecting to outside (eg respiratory, GI, GU tract)

in the epithelium and connective tissue (lamina propria + muscularis mucosae)

Question 20

Locations where serous membrane are located?

Answer 20

Lining of peritoneal, pleural and pericardial cavities

in the mesothelium and connective tissues

Question 21

Connective tissue origins?

Answer 21

From the mesoderm: undifferentiated mesenchymal cells (resident cells) AND hematopoietic stem cells (transient cells)

Question 22

What cells derives from mesenchyme?

Answer 22

Chicken wing -

fibroblasts (the meat)
osteoblasts (bone)
Chondroblast (cartilage)
adipocyte (fat)

Question 23

What cells derive from blood?

Answer 23

RBC
Megakaryocyte (platelet)
basophil, eosinophil, neutrophil, lymphocyte
monocyte
mast cell

Question 24

Features of connective tissue?

Answer 24

1) NO cellular junctions
2) DOES NOT rest on basement membrane
3) Rich blood supply
4) No cytokeratin
5) abundant ECM

Question 25

Types of connective tissue?

Answer 25

Embryonic connective tissue: mesenchyme, mucous connective tissue (eg umbilical cord) mesenchyme differentiates into: 1)connective tissue proper (lamina propria, dermis of skin, tendon, ligament) 2) specialized connective tissue (bones and cartilage, adipose tissue) 3) hematopoeitic tissues (may not be from mesenchyme)

Question 26

Composition of connective tissue?

Answer 26

Extracellular matrix, cellular component

Question 27

Extracellular matrix components?

Answer 27

Fibrous components, ground substances fibrous components: collagen 3, collagen 1 (MOST ABUNDANT), elastic fibers (elastin, fibrillin) ground substances: proteoglycan: core protein + GAG - component of hyaluronic acid glycoprotein

Question 28

Types of cartilage? Their appearance/morphology?

Answer 28

Hyaline - glassy, less cells fibrocartilage - regular fibers elastic cartilage - bundles of irregularly arranged elastic fibers

Question 29

Loose connective tissue examples?

Answer 29

Lamina propria, mesentery

Question 30

Dense connective tissue types and examples?

Answer 30

Dense irregular: dermis of skin dense regular: tendons, ligaments, aponeurosis

Question 31

Functions/morphology of cellular components of connective tissues?

Answer 31

Fibroblast: Synthesize fibrous components and ground substance (ECM) Fibroblast (active) > fibrocyte (quiescent) Macrophage: For ingestion of particles and digestion by lysosomal enzymes, For immune defense (antigen presentation, secrete growth factors & cytokines) Phagocytic, from monocyte Mononuclear phagocyte system Kupffer cells in liver, microglial cells in CNS, Langerhans cells in skin, osteoclasts in bone Mast cell: Cell surface receptors for IgE, Granule (heparin, histamine) release triggered by antigen binding to IgE Plasma cell: From B cell, for synthesis of antibody, Eccentrically placed nucleus (clock-face), basophilic cytoplasm Leukocyte: Migrate from blood during inflammation Neutrophil, eosinophil, basophil, lymphocyte Adipose cell Unilocular (white) vs multilocular (brown) White: main energy source Brown: numerous mitochondria, important in first few months postnatal

Question 32

Properties of type 1 skeletal muscle? (in terms of: 1)color and/or oxidative property 2) twitch and fatigue 2)myoglobin/mitochondria/blood capillary content, 3) contraction time and respiration type, 4) ATP enzyme velocity and ATP production mechanism

Answer 32

1) red meat, slow oxidative 2) slow twitch, fatigue resistant 3) high amount of myoglobin, mitochondria, blood capillaries (so appears red?) 4) long and slow contraction, aerobic respiration 5) lower ATP enzyme velocity, ATP produced by oxidative phosphorylation

Question 33

Properties of type 2a skeletal muscle? (in terms of: 1) oxidative property 2) twitch and fatigue 3)myoglobin/mitochondria/blood capillary content, 4) contraction time and respiration type, 5) ATP enzyme velocity and ATP production mechanism

Answer 33

1) fast oxidative glycolytic 2) fast twitch, fatigue resistant 3) intermediate between type 1 and 2b 4) intermediate contraction time (faster than type 1 but slower than type 2b), can be both aerobic/anaerobic respiration 5) intermediate ATP enzyme velocity, both oxidative phosphorylation and glycolysis used for ATP production

Question 34

Properties of type 2b skeletal muscle? (in terms of: 1) oxidative property, color 2) twitch and fatigue 3)myoglobin/mitochondria/blood capillary content, 4) contraction time and respiration type, 5) ATP enzyme velocity and ATP production mechanism

Answer 34

1） fast glycolytic, white meat 2) fast twitch, fatigue prone 3) lowest amount of myoglobin, mitochondria, blood capillaries compared to t1 and t2a 4) fast contraction time, anaerobic respiration 5) fast ATP enzyme velocity, exclusively by glycolysis

Question 35

which 2 muscle types are striated and their distribution

Answer 35

cardiac (walls of heart, vena cava, pulmonary vein) skeletal (attached to skeleton or visceral tissue)

Question 36

smooth muscle distribution

Answer 36

walls of blood vessels, glands, organs, viscera

Question 37

cellular unit of skeletal muscle?

Answer 37

1 muscle fiber - formed of multiple myogenic cells fused together

Question 38

How are the calcium releasing units arranged in skeletal and cardiac muscle

Answer 38

c+t+c in skeletal, triad at AI junction c+t dyad in cardiac, at Z line

Question 39

Functions and morphology of intercalated discs of cardiac muscle?

Answer 39

Adhering junction - transverse, the z line for muscle attachment desmosome - transverse and lateral, protect gap junction from stretch and tear gap junction - lateral, for transmission of electrical synapse and synchronized muscle contraction

Question 40

Which muscle type has NO t tubule

Answer 40

smooth muscle

Question 41

nucleus position of the types of muscle cells?

Answer 41

skeletal: peripheral cardiac, smooth: central

Question 42

Muscle response to increased demand?

Answer 42

Skeletal, cardiac: hypertrophy ONLY smooth: hypertrophy and HYPERPLASIA

Question 43

CNS components of white and gray matter? and functions of white and gray matter?

Answer 43

gray: for synapses - neuron cell body, glial cells, unmyelinated neuropil, capillaries white body - for signal transmission (like wires): glial cells, myelinated axons

Question 44

PNS components?

Answer 44

Ganglion - cell bodies, nerves: bundles of myelinated/unmyelinated axons and glial cells

Question 45

Examples of pseudounipolar and bipolar neurons?

Answer 45

Pseudo: dorsal root ganglion cell bipolar: retina, olfactory cells

Question 46

Initial region of axon function?

Answer 46

Initiate action potential

Question 47

CNS neuroglia? Functions?

Answer 47

Astrocytes (white matter: fibrous, grey matter: proteoplasmic), ependymal cells, microglia, oligodendrocyte astrocyte: maintain blood brain barrier, injury response, physical and metabolic support for neurons, buffer electrolyte and neurotransmitter ependymal cells: composes part of choroid plexus to produce CSF oligodendrocyte: accelerate transmission of action potential, electrical insulation and protection microglia: immune surveillance, antigen presentation, phagocytic, remove debris in injury

Question 48

PNS neuroglia?

Answer 48

Schwann cells (axons), perineuronal satellite cells (ganglion)

Question 49

PNS injury and regeneration?

Answer 49

1) lots of toxic debris 2) debris removed very quickly 3) wallerian degeneration 4) schwann cells form myelin sheath to reach original target 5) axon grows back to function normally

Question 50

CNS injury and regeneration?

Answer 50

1) lots of toxic debris 2) microglia cannot move to remove debris quickly because of BBB 3) astrocytes rush to rescue and forms glial scar 4) regeneration route completely cut off by glial scar 5) debris still present, releases inhibitors to prevent regeneration

Question 51

Skin layers? the appendages?

Answer 51

Epidermis, dermis, subcutaneous layer appendages: hair, nails, adnexal structures (pilosebaceous units, eccrine, apocrine glands)

Question 52

Epidermis layers from bottom to surface? how long does it take for cells to proliferate up to surface? What cells make up epidermis?

Answer 52

Stratified basale, stratified spinosum, stratified granulosum, stratified corneum, 30 days, keratinocytes

Question 53

Function of dermo-epithelial junction?

Answer 53

Adhesion - pemphigoid blister results as epidermis loses adhesion cellular migration (for wound healing) cellular signalling between epithelium and dermis

Question 54

The most abundant type of collagen in connective tissue? The types of collagen in epidermis to connective tissue?

Answer 54

Collagen 1 epithelium: 7 basal lamina: 4 reticular lamina: 3 connective tissue: 3,1

Question 55

2 layers of basement membrane?

Answer 55

Basal lamina, reticular lamina

Question 56

Functions of subcutis?

Answer 56

Calorie reserve heat insulation cushion effect

Question 57

Origin of pilosebaceous unit?

Answer 57

Epidermal downgrowth

Question 58

Pilosebaceous unit composition?

Answer 58

hair follicle, arrector pili muscle, sebaceous gland

Question 59

4 types of pilosebaceous unit? locations?

Answer 59

TVAS: terminal (scalp and beard area) vellus: majority of body Apopilosebaceous: axilla, groin sebaceous: face, back, chest

Question 60

Hair follicle comparison between scalp and forehead?

Answer 60

scalp: terminal hair follicle, larger follicle, extends to subcutis, smaller sebaceous gland forehead: vellus hair follicle, smaller follicle size, larger sebaceous gland

Question 61

Causes of androgenetic alopecia?

Answer 61

Proportion of hair shifts from terminal to vellus

Question 62

Hair cycle processes and how long each takes for scalp hair? What % of hair in each phase? how long is the hair cycle for eyebrow?

Answer 62

anagen (active growing phase) - 3 years, 90% catagen (transition to quiescence) -3 weeks, ~1% telogen (resting) - 3 months, ~10% 4 months

Question 63

Telogen effluvium causes and consequences?

Answer 63

Physical, psychological stress, 70% hair follicles enter telogen prematurely

Question 64

Sebaceous gland vs eccrine sweat gland vs apocrine sweat gland - locations, opening, secretions? glabrous skin vs hair-bearing skin (locations, what it contains)

Answer 64

Locations: sebaceous: only in hair-bearing skin apocrine: axilla, genitalia, mammary areas eccrine: most of the body secretions: sebaceous: oily, apocrine: lipid-rich production eccrine: active sweating during thermoregulation openings: sebaceous: open into spaces around hair root apocrine: open into axillary and other hair follicles eccrine: open into skin surface glabrous skin: palms and soles only, have encapsulated sensory organs BUT no hair follicles and sebaceous glands Hair-bearing skin: most of the body, NO encapsulated sensory organs, have hair follicles and sebaceous glands

Question 65

Embryonic origin of skin?

Answer 65

ectoderm: epithelium, nervous system mesoderm: dermis, skin appendages

Question 66

Skin functions?

Answer 66

1) barrier through stratified corneum (cornified cell envelope with glutamyl-lysyl isodipeptide bonds, fatty acids prevents inward and outward passage of water) 2) UV absorption - by stratum corenum, epithelial keratinocytes, melanin (melanin produced by melanocytes, then transferred as melanosomes to keratinocytes (hair production)) 3) Thermoregulation (shivering/sweating/circulation alteration) 4) immune response (innate + adaptive) - innate: dermal dendritic cells, macrophages doing phagocytosis, antimicrobial peptides, alarmins adaptive immunity: antigen-presenting cells trigger Th1, Th2 response 5)Sensation (eg Meissner's corpuscles/Merkels's receptors) 6) Vitamin D synthesis 7) homeostasis (regeneration of skin appendages/proliferation etc)

Question 67

Skin stem cell location?

Answer 67

- Bulge area of follicles – Basal area of the inter-follicular epidermis – Base of sebaceous glands

Question 68

Perspiration types? How is active sweating controlled (in terms of nervous innervation)?

Answer 68

Insensible (passive water evaporation from skin surface) Active sweating from eccrine sweat glands Sympathetic innervation, cholinergic, stimulated by pilocarpine and inhibited by atropine

Question 69

Arrange Erysipelas, cellulitis and necrotizing faciitis in terms of how deep the level or redness is?

Answer 69

Erysipelas (epidermis/upper dermis) > cellulitis (dermis) > necrotic faciitis (deep fascia)

Question 70

Cell cycle steps?

Answer 70

G1 phase, S phase, G2 phase, M phase

Question 71

Sequence of CDKs and cyclins? The complex's functions?

Answer 71

CDK: 4/6, 2, 2, 1 cyclins: DEAB CDK4/6, cyclin D: move cell from G0 to G1 and prepare it to move from G1 to S CDK2, cyclin E: prepares cell for DNA replication CDK2, cyclin A: Activate DNA replication inside nucleus for S-phase CDK1, cyclin B: Promote mitotic spindle assembly, reorganizes cytoplasm to prep for mitosis

Question 72

Know that: Retinoblastoma as eye cancer in children RB inactivating mutations Inhibitor effect on E2F > phosphorylated to kickstart replication CDK4/6i in use to treat breast cancer (with hormonal therapy) CIP/KIP and INK4 proteins remember p16, p21, which p21 is regulated by p53

Question 73

Mechanism and function of p53 and p21?

Answer 73

DNA damage > p53 protein p53 phosphorylated and activated p53 binds to regulatory region of p21, activates p21 transcription > p21 translation p21 inactivates G1/S-CDK-cyclin complex and S-CDK/cyclin complex Function: leads to cell cycle arrest If anything serious leads to DNA repair and then apoptosis