2. Cells and Tissues Flashcards
Write the hierachy of a cell
- cell membrane (phospholipids, cholesterol, proteins)
- nucleus (nuclear membrane, chromosomes (Containing DNA)
- cytoplasm
- cytosol (viscous fluid that suspends other contents, mainly water but also proteins and solutes)
- organelles
- inclusions (chemical substances eg. stored nutrients- not present in all cell types)
define Mitochondria
energy powerhouse for cell
produces ATP
define function of Ribsomes
free - makes proteins for intracellular use
attached to RER- proteins for use in the cell membrane / extracllular use
define function of golgi apparatus
modifies, concentrates / packages proteins and lipids made by ER into membrane bound vesicles
vesicles are stored and then move to plasma membrane for exocytosis as req
define function of lysosomes
garbage collection- digest foreign material, breakdown dead organelles,
define function of Cytoskeleton
- cell scaffolding- network of rods throughout the cytosol that provide structure
- includes microfilaments / microtubules/ intermediate filaments
define function of centrosome
play role in cell division (mitosiss) - anchor point for microtubules to separate centromeres into chromatids
form a base for cilia / microvilli / flagella
define function of cilia
- fine/ hair like extensions on cell surface to move substnaces across cell surface- e.g. dust out of trachea
define function of microvilli
- finger like projections to increase surface area of cell
define function of flagella
- long extension that propels cell for transprot
define function of nucleus
- contains DNA which contains instructions for protein building -which protein to synthesize, and how much.
-also controls cell growth and reproduction (Cell division)
most cells have 1 nucleus, but some have multi (those involved in frequent cell division)/ none (mature erthrocytes)
define function of Nucleic acids
- DNA
genetic material found in nucleus
composed of nucleotides (A,T, G, C)
23pairs of chromosomes (46 in total in each body cell, except sex cells)
RNA- nucleotides (AU,G,C)
involved in protein synthesis (decodes / sends messages on behalf of DNA)
define function of Protein synthesis
made through DNA which provides unique code of nucleotides (A,T,C,G).
MRNA decodes nucleotides and creates complementary code (into triplets) based on AUCG, and transports new seq to ribosomes outside nucleus
tRNA than bring AA which correspond with the mRNA triplets, forming new proteins
Describe structure and function of muscle tissue
specialised myocytes that can contract, to provide movement of bones and substances through hollow organs
3 types
- skeletal muscle (muscle attached to bones)- brings about body movements
- smooth muscle- found in walls of hollow organs (uterus)
- cardiac muscle - found in walls of heart
What are glands
Composed of 1+ epithelial cell that make / secrete particular products called secretions
2 types
- Endocrine: secrete hormones into the bloodstream
- Exocrine: secrete their substance onto a body surface or into a body cavity, most often via a duct; are usually multicellular
- Secretory glands include kidneys/ pancreas / mammary / sebaceous/ sweat /
mucous
Describe general function and structure of CT
The most abundant type of tissue in the body
Functions:
Binding and support
Protection
Insulation
Transportation (of substances within the body)
Structure: there are two main components to connective tissue
Cells
Matrix, composed of: Ground substance / Fibres
describe location + function of Simple squamous epithelium
very thin to enable rapid diffusion
example- filtering units of kidneys enable rapid diffusion and filtration of blood
describe location and function of simple cupoidal epithelium
cuboidal shape provides greater surface area for secretion and absorption
simple- very thin passage
e.g. line surface of ovarian surface epithelium- simple cuboidal cells have ability to rapidly divide, which enables tehm to repair defects that occur on overian surface. studies have linked majority of ovarian cancer causes to simple cuboidal layer
describe location and function of stratified squamous (keratinised and non-keratinised)
keratinised
- apical layer of dead skin that is in dry surface.
- stratified structure provides protection from mechanical / chemical damage
- keratinised surface is impervious to water- ‘waterproofing’ surface, creating better protection against abrasions
- non-keratinised
- apical layer of skin that is in a wet environment (E.g. mouth / vagina)
- non-keratinised surface is moist and containst living cells in surface layer
- provides moderate protection against abrasions
Describe loose Connective Tissue
- Areolar:
- has various cells, loose arrangements of fibres
- connects and surrounds most body structures
- most widely distributed, found under most epithelia and skin, surrounds small blood vessels, nerves and glands
- Adipose (fat)
- composed of mainly adipose cells
- stores nutrients + provides insulation
- found in subcutenous tissue, around kidneys, eyeballs, abdomen and hips
- 2 types - white + brown (generates body heat, esp in babies)
- Reticular- internal framework for free blood cells- lymph nodes, spleen, bone marrow
Describe Dense CT
Regular-
- closely packed bundle of collagen fibres, parallel to each other
- creates strength in one direction
- found in tendons / ligaments and fascia
Irregular
- bundle of collagen fibres in an irregular arrangement
- provide resistance to tension from numeous direction
- found in dermis, joint capsures
Elastic
- contains elastic fibres
- found in a few ligaments, large blood vvessels and bronchi of lungs
Describe CT- Cartilage
Tough yet flexible - precursor structure to all bones
Resists both tension and compression forces
avascular / no nerve supply
3 types
- hyaline cartilage- most common / end of long bones
- elastic cartilage - tip of nose / btween ribs and sternum
- fibrocartilage- within certain joints (e.g. pubic symphysis). absorbs compressive shock and provides tensile strength
Describe CT- Bone
support and protection of various body structures
attachment site for muscles (via tendons) allowing movements
rigid and inflexible- stores minerals (ca and phosphates) in the matrix
provides cavities for fat storage and blood cell production
