ILS-3 histology

Question 1

Cell Biology (Cytology)

Answer 1

Studies the cell’s– structure, composition, metabolism, cycle, function, behavior, and communication

Question 2

first two scientists to discover cells under the microscope

Answer 2

Robert Hooke , Antoni van Leeuwenhoek

Question 3

how are cells studied

Answer 3

Study of cells through– cell culture, microscopy techniques, cytometry, and cell fractionation

Question 4

Histology

Answer 4

study microscopic structure of normal biological cells and tissues

using light and electron microscope

Question 5

main uses of Histology and Histopathology:

Answer 5

1. show changes in tissues that occur at cellular level

ii) Medicine– identification of normal and abnormal tissue, diagnosis, and analysis of effects of treatment

iii) Autopsies and forensic investigations– for identifying the cause of death from microscopic
tissue examination

Question 6

how are tissues prepared

Answer 6

Tissue (sample) preparation and processing– selection, sectioning, trimming, embedding in a harder medium, and chemical fixation

Question 7

with what are tissues stained

Answer 7

Tissue staining– Hematoxylin stains cell nuclei blue, and

Eosin stains the cytoplasm and other tissues in pink

Question 8

Hematoxylin

Answer 8

Hematoxylin stains cell nuclei blue, and

Question 9

Eosin

Answer 9

Eosin stains the cytoplasm and other tissues in pink

Question 10

tissue examples

Answer 10

group of cells with a similar structure that have a definite and unique function
– include epithelial tissue, connective tissue, nerve tissue, and muscle tissue

Question 11

cell

Answer 11

Cell– basic microscopic building block of human body
– smallest and basic structural and functional unit of various organs essential for sustaining life

Question 12

Plasma membrane

Answer 12

Plasma membrane– lipid bilayer (phospholipid, cholesterol, hydrophilic head, hydrophobic tail)

-passive and active transport

• cell adhesion, ion conductivity, and cell signaling

-provide attachment surface for several extracellular structures and intracellular network of cytoskeleton

-lipid-soluble substances (e.g, oxygen, carbondioxide, and nitrogen,

-water-soluble substances (e.g, ions, glucose, aminoacids, and water,

Question 13

cytosol (cytoplasm)

Answer 13

Sodium is the major cation in extracellular fluid (ecf)
– Potassium is the major cation in intracellular fluid (icf)
– Calcium, Chloride, and Bicarbonate are present in relatively more concentration in ecf
– Magnesium, and Proteins are present in relatively more concentration in icf

Question 14

nucleus

Answer 14

Nucleus– surrounded by nuclear membrane (nuclear pores), contain genetic information (DNA/chromosomes/chromatin), controls cell growth and multiplication by regulating gene expression, initiating cellular reproduction, site for DNA replication and RNA synthesis using DNA as template (Transcription), contain nucleolus (rRNA is made)

Question 15

Ribosomes-

Answer 15

protein synthesis (translation– During translation, ribosomes synthesize polypeptide chains from mRNA template molecules),

Question 16

Rough endoplasmic reticulum (RER)

Answer 16

synthesizes proteins in sacks called cisternae

Question 17

compromised structure and functions of RER can lead to these diseases

Answer 17

diabetes, inflammation, and neurodegenerative disorders including Alzheimer’s disease, Parkinson’s disease, and bipolar disorder

Question 18

Smooth endoplasmic reticulum functions

Answer 18

– carry out synthesis of lipids (e.g, cholesterol) and phospholipids and secretion of steroid hormones

store and release of calcium ions (e,g, in muscles– sarcoplasmic reticulum

detoxification of natural metabolic products, alcohol, and drugs

Question 19

Golgi apparatus/body/complex:

Answer 19

sorts new proteins made on RER, perform post-translational modifications (e.g, glycosylation, etc) in newly synthesized proteins, packages proteins and carbohydrates into membrane-bound transport vesicles for export from the cell

Question 20

Diseases-related genes associated with Golgi apparatus include–

Answer 20

some of the neurodegenerative diseases, cancer, infectious diseases and cardiovascular diseases, etc

Question 21

Mutations in the genes encoding Golgi resident proteins can trigger the occurrence of diseases–

Answer 21

result in defects in membrane trafficking, mislocalization of proteins, impaired glycosylation of proteins, and the accumulation of undegraded proteins

Question 22

Mitochondria-

Answer 22

Mitochondria– cristae (folds), matrix, contain mitochondrial DNA (self replicated by DNA polymerase), powerhouse of cell (generates energy in the form of adenosine triphosphate [ATP] through the process of glycolysis, tricarboxylic acid [TCA/ Citric acid/ Krebs] cycle, electron transport chain-oxidative phosphorylation pathways), degeneration can result in severe energy loss (and can manifest e,g, as muscle weakness

Question 23

Lysosome-

Answer 23

contain hydrolytic enzymes perform digestion of cell nutrients due to presence of the digestive enzymes, continuously break down old proteins, foreign materials, and various wastes, bring about phagocytosis (in which foreign materials are brought into the cell and chewed up), can open up in cell itself causing programmed cell death (apoptosis)

Question 24

peroxisome

Answer 24

Peroxisome– contain catalase (destroy free radicals), involved in the oxidation of long chain fatty acids and synthesis of glycolipids

Question 25

Mitochondrial diseases can affect various structures of human body:

Question 26

Microtubules-

Answer 26

primarily made up of tubulin protein cilia, flagella are made of microtubules for locomotion dynein and kinesin motoe proteins made of mt

Question 27

centrioles

Answer 27

centriole (made of mt), divide during cell division (mitosis) and the two parts move to opposite sides of the dividing cell

Question 28

Microfilaments they are involved in what:

Answer 28

made of actin, essential part of cell cytoskeleton involved in muscle contraction, cell support, and pinching-off of daughter cells after mitosis (cell division)

Question 29

Vacuole-

Answer 29

containing triglycerides/triacylglycerol)

Question 30

what happens during cell signaling? and what changes occur

Answer 30

during cellular signaling, a ligand binds a cellular receptor-- binding results in a cellular effect, which manifests as a variety of changes in that cell, including altering gene transcription or translation or changing cell morphology

Question 31

Cellular signaling include:

Answer 31

autocrine signaling- paracrine signaling- endocrine signaling- signaling across gap junctions-

Question 32

cell injury leads to:

Answer 32

necrosis, apotosis

Question 33

Depletion of intracellular ATP during the cellular injury resulting in:

Answer 33

influx of sodium and calcium and osmotic swelling lactic acedosis severe intracellular acidosis clumping of nuclear chromatin (pyknosis)

Question 34

Epithelial tissue:

Answer 34

covers surfaces, form glands, lines body cavities, connected with each other through tight or loose junctions,

Question 35

Connective tissue

Answer 35

binds together and supports other tissues and organs, intercellular material

Question 36

Muscle tissue (fibers):

Answer 36

-- skeletal, smooth (e.g digestive tract), and cardiac muscles

Question 37

Nervous tissue-

Answer 37

sensory motor, mixed

Question 38

skeletal muscle cells

Answer 38

skeletal muscle cells: long tubular/cylindrical, striations in microscopic appearance, multinucleated

Question 39

cardiac cells:

Answer 39

striations in microscopic appearance, single nucleus, branch off from each other, joined to one another by intercalated discs that contain gap junctions

Question 40

smooth muscle cells:

Answer 40

spindle shaped, unstriated in microscopic appearance,

Question 41

Types of connective tissue:

Answer 41

i) Loose ii) Dense iii) Specialized

Question 42

Connective tissue:

Answer 42

-- made of cells (e.g fibroblasts) -- intercellular material (matrix)

Question 43

Loose connective tissue and examples

Answer 43

posses few fibers, with relatively large amount of ground substance, ssecreted by fibroblast contain collagen, elastic, and reticular fibers

Question 44

Areolar connective tissue--

Answer 44

Areolar connective tissue-- fibers are far apart from each other, found beneath epidermis, and hypodermis (skin), and underneath epithelial tissue of all body systems that have external openings component of the lamina propria

Question 45

subtypes of loose connective tissue:

Answer 45

Areolar connective tissue- Adipose connective tissue- Reticular connective tissue-

Question 46

Adipose connective tissue-

Answer 46

located beneath skin (subcutaneous fat), around internal organs (visceral fat), in bone marrow (yellow bone marrow), intermuscular, and in breast (breast tissue), composed of fat cells (adipocytes), store energy in the form of lipids (white adipose tissue), generates body heat (brown adipose tissue), cushions and insulates the body

Question 47

Reticular connective tissue is found____

Answer 47

found around the kidney, and liver, support the lymphoid organs (lymph node stromal cells),

Question 48

dense connective tissue

Answer 48

relative smaller amount of ground substance, have fibroblasts Dense regular connective tissue, Dense irregular connective tissue

Question 49

Specialized connective tissue: a) Cartilage– Hyaline (e.g, between bones in joints, costal cartilage attached to upper ribs, trachea, nasal septum) -- Fibrocartilage (tough collagen fibers, resistant to stretching, intervertebral discs, connect pelvic bones) -- Elastic (flexible, easily stretched, external ear, auditory tubes, epiglottis) -- cells (chondrocytes), cavities (lacunae)

Answer 49

a) Cartilage– Hyaline Fibrocartilage Elastic cells (chondrocytes), cavities (lacunae)