cells and tissues

Question 1

what is the basic structure of the bacterial cell wall?

Answer 1

bacterial cell walls are made from peptidoglycan (murein)

crosslinked polysaccharide chains cross linked by unusual peptides containing D-amino acids

Question 2

what is the difference between gram positive and gram negative bacteria?

Answer 2

gram positive have thick cell walls of several layers of peptidoglycan and stain purple when subjected to gram stain procedure.
gram negative have a relatively thin cell wall and are composed of a single layer of peptidoglycan surrounded by an outer membrane and are colourless when stained

Question 3

cell membrane structure and function

Answer 3

phopholipid bilyaer containing proteins that separate cytoplasm surroundings and are selectively permeable

Question 4

structure and function of nuclear membrane

Answer 4

composed of inner and outer membrane separated by perinuclear spaces. it keeps DNA inside the nucleus and protects it from materials in the cytoplasm

Question 5

mitochondria structure and function

Answer 5

site of aerobic resiration
double membrane- inner membrane is folded into cristae
has own ribosomes

Question 6

RER structure and function

Answer 6

made up of cisternae, tubules and vesicles and main function is to produce proteins

Question 7

SER structure and function

Answer 7

synthesis of lipids, steroid hormones and detoxifaction of harmful metabolic by products

Question 8

golgi complex structure and function

Answer 8

double membrane sacs forming cisternaw, it modifies, sorts and packages proteins for secretion

Question 9

lysosomes structure and function

Answer 9

membrane bounds vesicles containg hydrolytic enzymes

Question 10

peroxisomes structure and function

Answer 10

break down fatty acids that are used for membrane formation and fuel for respiration. they are single membrane bound organelles with lipids and proteins that act as enzymes

Question 11

cytoskeleton structure and function

Answer 11

gives cell shape, offers support and facilitates movement via microfilaments and microtubules

Question 12

how are sections cut in histology?

Answer 12

tissue samples are fixated to preserve it.
either aldehyde,alcohol, oglutaraldehyde or ethanol.

then cut up tissue

then process the tissue - the aim itsd to get thin slices but also stiff and resistant to mechanical trauma. - do this by setting in wax:

1. dehydration- remove water by alcohol
2. clearing -replace alcohol with xylene
3. wax infiltraion - replace xylene with parafin wax
4. embedding/blocking out - orientate tissue to form a block

then cut up tissue into thin slices

Question 13

what is H&E staining?

Answer 13

haematoxylin stains acidic structures purple - hence nuclei are purple

eosin acidic dye stain basic structures pink, hence proteins in the cytoplasm are pink

Question 14

what are the 7 main functions of eptithelia

Answer 14

absorption
surface movement
secretion
gas exchange
surface lubrication
sensation 
protection

Question 15

what is special about the epithelia in airways, testes and fallopian tubes?

Answer 15

all have cilia for surface movement

Question 16

gas exchange epithelia specialisation?

Answer 16

squamous epithelium

Question 17

what are tight junctions?

Answer 17

occulding/claudin seals to stop protein movement of substances across epithelium through intracellular spaces

Question 18

what are adherens junctions?

Answer 18

transmembrane proteins that connect across cell cytoskelton below tight junctions

Question 19

what are gap junctions

Answer 19

small channels that allow intracellular ion/small molecule exchange

Question 20

what are demsosomes

Answer 20

transmembrane proteins that connect to other adjacent cells

Question 21

Hemi -desmosome/focal adhesions?

Answer 21

provide attachment to underlying basal lamina

Question 22

what is the difference between endocrine and exocrine glands?

Answer 22

endocrine glands dont have ducts and secrete directly into the blood.

exocrine glands have ducts, releasing onto surface

Question 23

what would you call a duct which is unbranched?

Answer 23

simple

Question 24

what would you call a duct which subdivides?

Answer 24

branched or compound

Question 25

what would you call a duct which coils/ tubular with branches?

Answer 25

alveolar / acinar

Question 26

what are the 3 types of exocrine glandular secretion?

Answer 26

merocrine apocrine holocrine

Question 27

what happens in merocrine secretion?

Answer 27

proteins are in intra-cellular vesicles that fuse with cell membrane and are excreted by exocytosis.

Question 28

what happens in apocrine secretion?

Answer 28

protein product is inside vesicles, the vesicles approach the apical memrbane and the membrane pinches off with loss of some apical membrane

Question 29

what happens in holocrine secretion?

Answer 29

secretory product accumulates in the cytoplasm and the cell disintegrates to release the product

Question 30

naming of epithelia associated with layering?

Answer 30

single layer = simple | multiple layers = stratified

Question 31

naming of epithelia associated with cell shape

Answer 31

look at top layer of cells squamous cuboidal columnar

Question 32

specialisations and adaptations of epithelia?

Answer 32

cilia microvillio keratinisation

Question 33

what are the 4 types of stratified epithelia?

Answer 33

stratified squamous epithelia stratified cuboidal epithelia stratified columnar epithelia transitional epithelia

Question 34

what are the 5 roles of endothelium?

Answer 34

``` structure metabollic defence storage repair ```

Question 35

what is epidermolysis bullosa?

Answer 35

herditary disorder causing blistering of the skin gene mutation leading to adhesion of molecules in the basement membrane causing abnormal anchoring of the epidermis to the dermis

Question 36

what is cystic fibrosis?

Answer 36

autosomal recessive disease due to a genetic mutation that stops the production of a proteim in cells of the lung, pancreas and other organs. the absence of the protein impairs the cells ability to transport chloride ions into and out of the cell causing thick muscus and bacterial infection of the lungs

Question 37

what is the composition of connective tissue?

Answer 37

extracellular matrix and fibroblasts

Question 38

what are the components of the extracellular matrix

Answer 38

ground substance - glycosaminoglycans (GAGs), proteins and glycoproteins fibres (collagen for strength, elastin for stretch) percolating tissue fluid (leaked from capillaries)

Question 39

5 types of connective tissue?

Answer 39

blood, blood vessels, lymph, cartilage and bone

Question 40

what is the structure and function of the basement membrane?

Answer 40

specialised form of extracellular matrix. ot surrounds cells amd lies underneath of epithelial cells and separates 2 sheets of cells consists of a mixture of collagen, laminin, entractin which bind together to make a highly cross-linked extracellular matrix works to anchor down the epithelium to its loose connective tissue (dermis) underneath

Question 41

what is in blood?

Answer 41

``` RBC platelets proteins hormones nutrients/metabollic waste gases plasma ```

Question 42

what is the structure of blood vessels?

Answer 42

tunica intima = inner lining - endothelium tunica media = muscular layer in the middle tunica adventitia = outer CT network

Question 43

what is the lymph system?

Answer 43

lymph nodes filter lymph which returns to blood at thoracic duct and right lymphatic duct. lymph contains white blood cells to fight infection lymphatic system is a network of tissues and organs that help get rid of the bodies toxins, waste and other unwanted materials

Question 44

the structure and function of cartilage

Answer 44

chondroblasts make the ground substance and collagen fibres (extracellular matrix) chondroblasts become trapped as chondrocytes, function of cartilage depends on its constituents

Question 45

structure of bones?

Answer 45

osteoblasts make osteoids (extracellular matrix) mineralised by calcium to make bone osteoblasts become trapped as osteocytes which maintain the bone osteoblasts resorb bone in response to stress/growth/calcium staus

Question 46

what kind of large tumour is associated with visual disturbances>?

Answer 46

pituitary tumours

Question 47

what myelinates axons in the spinal cord?

Answer 47

oligodendrocytes