Cells tissues and skin Flashcards
state the levels of structual complexity
atoms, molecules, organelles, cells, tissue, organ, organ system, organism
how many cells in the human body
50000 trillio
how many types of cells in humans
250
all cells have 3 features in common
plasma mem
cytoplasm
nucleua
what is cytoplasm composed of
cytosol or ICF
where does protein synthesis occur
on the ribosome
name the 2 types of endoplasmic reticulum
smooth and rough
functions of Endoplasmic Reticulum
synthesis
storage
transport
detoxification
Where would a lot of rough ER be found
in excretory cells
explain the process of synthesis and export of protein by the RER
- protein is synthesised on the ribosome and migrates into the rough ER cistern
- in the cistern the protein folds into functional shapes
- short sugar chains attach to protein to form a glycoprotein
- protein is packaged in a tiny membranous sac called a transport vesicle.
- transport vesicle buds from the RER and travels to the golgi apparatus for further processing
what are the functions of the Golgi apparatus
- modify, concentrate and packages proteins and lipids
- forms vesicles and distributes them
- within the cell
- move and become inserted within the PM
- move to the PM for the content to be exported out of the cell by exocytosis
what is the function of mitochondria
cellular resp. releases energy in the form of ATP
functions of lysosomes
digest biological material including proteins and cell debris
dispose of invading bacteria, viruses and toxins
recycle molecules
what are the 3 types of cytoskeleton
- microfilaments
- intermediate filaments
- microtubules
what are microfilaments made up of
a protein called actin, it contracts for movement
where can intermediate filaments be found
in between the other 2 types, it resists the pulling forces on the cell.
what is the function of microtubules
maintain cell shape and distributes cellular organelles
what are cilia
motile cellular extensions on the top of cells
function of cillia
sweep in wave like manner to move materials across the surface
function of microvilli
increase the SA of cell
what is the plasma membrane
thin and flexible boundary between the ICF and ECF
describe a selectively permeable membrane
membrane that allows certain substances to pass but not all
name the 2 components of a phospholipid molecule
- hydrophilic head
- hydrophobic tail
what is a lipid core
lipid tails face towards each other
what does a plasma membrane consist of
- phospholipids
- proteins
- cholesterol
- carbohydrates
what are the functions of peripheral proteins
supports the plasma membrane, enzyme or motor functions
what are the 2 things that integral proteins can act as
enzymes or receptors
what are the 2 things that integral proteins can be classified as
channels or carrier
what is the main structual differences between peripheral proteins and integral proteins
not embedded throughout the plasma mem // embedded within the plasma mem and spans the entire membrane
why are integral proteins required within the plasma membrane
transports substances that need to pass through the PM but can’t pass directly through the lipid core because they are water soluble or too large.
Briefly describe a leakage channel
always open at both ends
briefly describe a gated channel
open at one end and can open or close at the other end
list the 3 types of gated channels
voltage
mechanically
chemically
why would a substance use carrier proteins
lipid insoluble
substances that are too large to use chemical proteins
glucose, amino acids
list the 3 factors that affect the rate of movement
concentration gradient
size of the substance
temperature (warmer = faster)
compare the 2 types of transport
passive - no energy - move down concentration gradient - simple diffusion, facilitated diffusion and osmosis Active - requires ATP - move up gradient
definition for facilitated diffusion
assisted transport of large or lipid insoluble substances from an area of high concentration to low concentration across a plasma membrane using an integral protein.
during osmosis water can move in one of two ways
- through the phospholipid bilayer
2. through channel proteins called aquaporins.
high solute concentration - ______ water concentration
low solute concentration - _______ water concentration
low
high
osmosis definition
net diffusion of water through a selectively permeable membrane from an area of more water to an area of less when the solute can not pass through the membrane.
briefly describe the sodium / potassium pump
moves NA out of the cell against concentration gradient
moves K into the cell against concentration gradient
exocytosis vs endocytosis
exo - out of the cell
endo- into the cell
definition for tonicity
ability of a solution to affect the shape of a cell by altering the cells internal water volume.
the tonicity of a solution that surrounds the cell is determined by what
concentration relative to ICF
describe isotonic solutions
same concentration as the ICF
describe a hypertonic solution
higher concentration of impermeable solutes than the ICF
lower amount of water than cell
what happens to a cell in a hypertonic solution
lose water - shrinks - crenates
describe a hypotonic solution
lower concentration of impermeable solutes than the ICF
higher amount of water than the cell
what happens to cells in a hypotonic solution
they will gain water and swell / burst / lyse
name the 4 types of tissue
epithelial
nervous
connective
muscle
what are muscle cells composed of
contractile microfilaments
name the 3 types of muscle tissue
skeletal
cardiac
smooth
name 3 places where would could find epithelial tissue
- covering the body
- line internal organs
- form glands
epithelium lacks blood vessels and is therefor refered to as _________
avascular
how does epithelium receive oxygen and nutrients?
delivered from underlying connective tissue via diffusion
epithelium has 2 structural adaptations
cillia and microvilli
list the 5 types of epithelial tissue
- simple
- stratified
- squamous
- cuboidal
- columnar
function of simple epithelial tissue
absorption
secretion
filtration
functions of stratified epithelium
protection
name the 4 classes of connective tissue
CT proper (loose and dense)
cartilage
bone
blood
what do all connective tissues have in common
all contain
- specialised cells
- ground substance
- protein fibers
describe the extracellular matrix
non living substance surrounding the cells it is composed of ground substances and protein fibers.
list the 3 types of protein fibers that connective tissue is made up of
- collagen fibers
- elastic fibers
- reticular fibers
functions of connective tissue proper
support, binding, storage and insulation
3 types of cartilage
hyaline, elastic and fibrocartilage
what does bone consist of
anundant collagen fibers
what reabsorbs bone as needed?
osteocytes
where is stratified squamous epithelial tissue found in the skin
epidermis
where is the connective tissue found in the skin
dermis and hypodermis
where is the smooth muscle tissue found in the skin
in arterioles that are attached to hairs - arrector pili
where is nervous tissue in the skin
all layers including sensory and motor
average SA of skin
2m 2
average weight of skin
4-5 kg
list the 3 major skin layers
epidermis
dermis
hypodermis
how often is your epidermis layer replaced
every 25-45 days
5 epidermal layers
stratum corneum lucidum granulosum spinosum basale
5 cell types in the epidermis
- epidermal stem cells
- keratinocytes
- melanocyte
- merkel / tactile cells
- langerhans cell
functions of the skin
- protection
- sensation
- metabolic function
- excretion
- blood reservoir
- temp reg.
why does the skin thin when aging
more cells lost than formed
why do elderly have higher chance of Skin cancer
increased number of melancytes
describe the stages of tissue repair
- inflamation (clot)
- organisation or proliferation
- maturation or remodeling
