Cytology

Question 1

What are the five basic functions of a cell?

Answer 1

Responsiveness, Movement, Metabolism, Growth, Reproduction

Question 2

What are the three components required for tissue formation?

Answer 2

Cells, Extracellular matrix (ECM), Tissue fluids

Question 3

Define a tissue.

Answer 3

A group of cells with the same embryological origin performing a similar function.

Question 4

What are the four basic tissue types?

Answer 4

Epithelial, Connective, Muscular, Nervous

Question 5

What is an organ?

Answer 5

A group of tissues with different functions that collectively perform a specific function.

Question 6

What is an organ system?

Answer 6

A group of organs with combined functions necessary for life.

Question 7

What is the modern theory describing the cell membrane structure?

Answer 7

Fluid Mosaic or Unit Membrane Theory

Question 8

What are the main components of the plasmalemma?

Answer 8

Lipids (phospholipids, cholesterol, glycolipids) and proteins (integral and peripheral)

Question 9

What is a lipid raft and its function?

Answer 9

A membrane substructure that reduces fluidity and restricts protein movement; contains caveolins for signaling and protein uptake.

Question 10

What is the glycocalyx and its function?

Answer 10

A carbohydrate-rich cell coat on the external membrane surface involved in protection, recognition, and cell interactions.

Question 11

What are the two main components of the nucleus?

Answer 11

Nucleolemma (nuclear envelope) and Nucleoplasm (karyoplasm)

Question 12

What is the structure of the nuclear envelope?

Answer 12

A double unit membrane with a perinuclear space, nuclear pores, and continuous with the rER.

Question 13

What is the nuclear lamina?

Answer 13

A fibrous layer of lamin filaments giving mechanical strength to the nucleus.

Question 14

What are the four components of nucleoplasm?

Answer 14

Chromosomes, Nucleolus, Nuclear matrix, Nuclear sap

Question 15

What is the difference between euchromatin and heterochromatin?

Answer 15

Euchromatin is uncoiled, metabolically active DNA; heterochromatin is coiled, inactive DNA visible as dark patches.

Question 16

What is a Barr body?

Answer 16

A heterochromatic, inactivated X chromosome in females, visible at nuclear periphery or as drumsticks in neutrophils.

Question 17

What is the function of the nucleolus?

Answer 17

Production of ribosomes

Question 18

What is the function of nuclear sap?

Answer 18

Provides medium for diffusion of metabolites and RNA

Question 19

What are the two types of ER?

Answer 19

Rough (rER) and Smooth (sER)

Question 20

What is the main function of rough ER?

Answer 20

Protein synthesis for secretion, lysosomes, and membranes

Question 21

What is ergastoplasm and where is it found?

Answer 21

rER in pancreatic acinar cells

Question 22

What is Nissl substance and where is it found?

Answer 22

rER in neurons

Question 23

What are the functions of smooth ER?

Answer 23

Lipid and phospholipid synthesis, detoxification, steroid production, calcium storage, chloride concentration

Question 24

What structures are found in mitochondria?

Answer 24

Outer membrane, inner folded membrane (cristae), matrix

Question 25

What are the functions of mitochondria?

Answer 25

Energy production via citric acid cycle, oxidative phosphorylation, fatty acid oxidation

Question 26

What are the two surfaces of the Golgi and their roles?

Answer 26

Cis (immature) - receives vesicles; Trans (mature) - ships secretory vesicles

Question 27

What are the main functions of the Golgi apparatus?

Answer 27

Packaging secretory products, glycoprotein/polysaccharide synthesis, lysosome production

Question 28

What is the origin of lysosomes?

Answer 28

Golgi apparatus

Question 29

What do lysosomes contain?

Answer 29

Hydrolytic enzymes for digestion

Question 30

What is a primary lysosome?

Answer 30

A vesicle that buds from the Golgi containing enzymes

Question 31

What is a secondary lysosome?

Answer 31

A lysosome fused with a phagosome where digestion occurs

Question 32

What are lipofuscin granules?

Answer 32

Indigestible remnants from lysosomal digestion (wear-and-tear pigments)

Question 33

What is the function of peroxisomes?

Answer 33

Degradation of hydrogen peroxide

Question 34

Where are peroxisomes commonly found?

Answer 34

Liver, kidney, and brown adipose tissue

Question 35

What does a centrosome consist of?

Answer 35

Two centrioles (diplosome) at right angles, surrounded by fibrous material

Question 36

What is the function of the centrosome?

Answer 36

Organizes microtubules and aids in cell division

Question 37

What are the three main cytoskeletal components?

Answer 37

Microtubules, Microfilaments, Intermediate filaments

Question 38

What is the function of microtubules?

Answer 38

Form cell skeleton, mitotic spindle, and components of cilia and flagella

Question 39

What proteins make up microfilaments?

Answer 39

Actin and Myosin

Question 40

What is the function of actin?

Answer 40

Muscle contraction, stabilizing cell shape, anchoring, and supporting microvilli

Question 41

What is the function of intermediate filaments?

Answer 41

Provide structural support and anchoring

Question 42

What are inclusions?

Answer 42

Non-essential structures that store metabolites or cell products

Question 43

Give examples of inclusions.

Answer 43

Glycogen granules, lipid droplets, pigment granules (melanin, hemosiderin, lipofuscin)

Question 44

Where are melanin granules found?

Answer 44

Iris, skin, uterus

Question 45

Where is hemosiderin commonly found?

Answer 45

In phagocytes in spleen, liver, and bone marrow

Question 46

What is lipofuscin?

Answer 46

Brownish pigment granule—end product of lysosomal digestion

Question 47

What are the three main types of intercellular junctions?

Answer 47

Occluding (tight), Anchoring (desmosomes, hemidesmosomes), Communicating (gap)

Question 48

What are occluding junctions also called and what is their function?

Answer 48

Tight junctions (Zonula occludens); create impermeable barriers between epithelial cells

Question 49

What transmembrane proteins form tight junctions?

Answer 49

Occludin and Claudin

Question 50

What are anchoring junctions composed of?

Answer 50

Zonula adherens, Desmosomes, Hemidesmosomes

Question 51

What do cadherins do in anchoring junctions?

Answer 51

Bind adjacent cells using calcium-dependent adhesion

Question 52

What filaments are involved in desmosomes?

Answer 52

Intermediate filaments (tonofilaments)

Question 53

What do hemidesmosomes connect?

Answer 53

Cells to the basement membrane via integrins

Question 54

What are gap junctions also called?

Answer 54

Nexus

Question 55

What proteins form gap junctions?

Answer 55

Connexons

Question 56

What is the function of gap junctions?

Answer 56

Allow electrical and chemical communication between cells

Question 57

What is a pleuripotent stem cell

Answer 57

a stem cell with with the potential to become any organ

Question 58

What is a multipotent stem cell

Answer 58

A stem cell with limited potential, which differentiates into an organ

Question 59

Differentiate between determinants and indeterminate growth

Answer 59

Determinant growth is limited. Growth stops when a certain size is reached. Example: heart, lung and muscle > permanently in the G0 phase Indeterminate growth is indefinite growth. Example is the liver and kidneys ( stable, only pause at G0), while bone marrow and skin = labile cells

Question 60

Hyperplasia vs hypertrophy

Answer 60

Hyperplasia is an increase in the number of cells (via mitosis) Hypertrophy is an increase in size (post-mitotic cell) via cytoplasm enlargement

Question 61

Differentiate between Apoptosis, necrosis and Autophagy

Answer 61

Apoptosis: genetically programmed cell death with no inflammation (sniper) Necrosis: >> inflammatory response (bom) Autophagy: cell eats/recycle damaged or redundant material

Question 62

Define Senescence

Answer 62

Permanent cell cycle arrest, telomere shortening, aging and inflammation