Slide 1 Flashcards
What makes a cell specialized?
since the DNA of all cells are the same:
- control of gene expression
- unique cell-specific transcriptomes and proteomes
What are the essential factors for differentiation in cell?
cell-cell communication
growth factors
ECM composition
cell location in differentiating embryo
What are the 3 major pathways for cell differentiation in stem cell?
- endoderm
- mesoderm
- ectoderm
What is gastrulation?
gives rise to primary germ, layers of endoderm, mesoderm and ectoderm
What do ectoderms give rise to?
skin cells (integument/skin), neurons (nervous system), pigment cell (lens of eyes)
What do mesoderms give rise to?
cardiac muscle skeletal muscle tubule cell of kidney red blood cell (circulatory system) smooth muscle (excretory system) (connective tissue)
What do endoderms give rise to?
lung cell (lining of digestive and respiratory tracts) thyroid cell pancreatic cell (parts of liver) (bladder)
What is a tissue? What are the 4 major types?
similar cells specialized to perform a certain function
- epithelial
- connective tissue
- muscle
- nervous
Describe the histology of a mammary gland tissue.
-columnar secretory epithelium
What is the function of epithelial?
- covers and protect body surface
- lines body cavities
- movement of substances
- glandular activity (secretory)
Where is epithelial found?
skin, linin of respiratory tract, digestive tract, urinary, glands of body
What is the function of connective tissue?
connect anchors, supports structure, transport, provides structural metabolic support
Where is connective tissue found?
bone, tendons, blood and fat
What is connective tissue made of?
polysaccharide matric, secreted and organized by cells in ECM (fibroblasts)
How can general connective tissues be organized?
loose or dense depending on the arrangement of fibres
What is common to all connective tissue except for blood?
They secrete ECM molecules like collagen to give support and form to structures
What are specialized forms of ECM?
tendons and cartilage
What are the functions of the muscle?
contract and generate force
What is the function of a nervous tissue?
initiate and transmit electrical impulse
Where is nervous tissue found?
brain, spinal cord and nerves
What is an organ?
made of different kinds of tissue to perform a special function
What tissues make up the stomach?
smooth muscle epithelium connective tissue loose connective tissue nervous tissue
How can death occur considering homeostasis?
can no longer be maintained.
disease is when it is disrupted.
What happened when there is low glucose? How can the body maintain homeostasis?
body slows glucose uptake and keep more in bloodstream, more glucose released by liver
What do negative feedback control systems do?
- inhibitory
- reset physiological variables
- maintain homeostasis
- more commone than positive feedback
What are positive feedback control systems?
- stimulatory
- amplify or reinforce change
- tends to produce destabilizing effects that disrupt homeostasis
- can bring to swift completion
eg. uterine contractions to deliver baby or action potential/depolarization
What is the difference between intrinsic and extrinsic control?
intrinsic: autoregulation
within tissues or organs
can involve chemical signals
extrinsic: regulation from organ to organ
- can involve nerve signals or endocrine signals (hormone)
What are the 3 levels of control? and differentiate them.
extrinsic: an organ acting on another (nerve, endocrine)
intracellular: cell effect on itself
intrinsic: a cell acting on another cell
What are fibroblasts?
cells that secrete matrix proteins
What is ground substance?
matrix of loose connective tissue
What are the different types of connective tissue?
Fibroblasts
-loose: more ground than fibres, gel
skin, organs under epithelia
-dense/irregular: more fibres than ground
muscle and nerve sheaths
-dense, regular: more fibres than ground
brown fat and white fat
-adipose: very little
Blood cells
-blood: acqueous
Chondroblasts
-cartilage: firm but flexible, hyaluronic acid
Osteoblasts and osteoclasts
-bone: rigid due to calcium
Where are dense connective tissues found?
tendons and ligament
What are tendons?
attach muscle to bone
What are ligaments?
attach bone to bone
What are collagen fibres like in tendons?
densely backed in parallel bundles
What are the two types of adipose connective tissue?
white (single lipid droplet) and brown (multiple lipid droplets)
Lipid droplets displace cytosol in adipose cells
What is the blood connective tissue made of?
blood: plasma matrix and free blood cells
Describe the two types of supporting connective tissues.
cartilage: light/flexible, trachea and ears
bone: calcified, rigid
Describe the physiology of the three different types of muscles.
Cardiac:
- striated
- intercalated disk
- nucleus
Skeletal:
- striated
- tappered
- multinucleus
Smooth:
- not striated
- single nucleus
Which tissue has an extensive amount of matrix?
connective
Which tissue has no blood supply and which other has no DIRECT blood supply?
- connective
2. epithelial
Which tissue has microvilli, cilia?
epithelial
What is the cell arrangement of epithelial?
variable layers, cells are either flattened, cuboidal or columnar
How do cells get a function?
differentiation which is achieved via control of gene expression
What does totipotent cell mean?
not yet differentiated
What are adult stem cells called?
pluripotent cells
found in the bone marrow!
Why stem cells important to medical therapies?
- undifferenciated cells gives rise to any cell type2. highly proliferative: self renewing in large quantitiesd to rapir tissue damage
How can we get stem cells? (tissues that are a perfect match to diseased individual)
- cloning: harvest somatic cell, mature blastocyst, treat in vivo with chemical cocktail and diferntiate into appropriate cell type and transplant back
danger: like cancer - adult bone marrow, testis stem cells but cannot make all cell/tissue types
- forced pluripotent stem cells created by 4 TF (Oct3/4, SOX2, c-Myc and KIf4) - virus to deliver 4 genes into fibroblast cells from adult mice
What are the 4 major structures of a cell?
plasma membrane, cytoplasm, nucleus and organelles
Distinguish a plasma membrane from an organelle membrane.
Plasma: encloses cell
organelle: sacs and canals made of same material as plasma membrane enclosing organelles like ER, Golgi etc.
membrane structure is made of lipid bilayer of PL molecules, hydrophobic so water soluble/water do not pass easily
What are the functions of membranes physiologically?
- control transport in and ut
- selectivity, receptivity and signalling (surface glycoproteins-immune system)
- anchor cytoskeleton or ECM for movement/structure
- cell signalling provides site for binding/catalysis
What are the 2 types of surface glycoproteins? How does the immune system take action/identify each type?
self markers MHC: on surface human cells unique to the individual (this cell is “self” to immune system)
self tolerance: ability of immune system to not attack our normal cells yet attack foreign cells
non-self markers: molecules on surface of foreign or abnormal cells/particles acts as flags for immune system as “non-self”
How is specificity given to a membrane protein (channel)?
shape of the molecule (can open or close_
What happens to the protein channels regulation of osmolarity during dehydration or increased salt consumption?
- release ADH
- ADH acts on distal tubule of kidney to increase water permeability
- inserts aquaporins channels into cell membranes
- water moves out of distal convoluted tubules of kidney by osmosis through ion channels thereby decreases osmolarity
- overall effect is increased water reabsorption by kidney and decrease urine flow
What are activities of an integral membrane protein?
bind to other integral membrane proteins to form cell cell conections, bind to ECM to give structure to tissues
What are integrins an examples of?
structural adhesion protein
- join cell to cell or cell to ECM
- heterodimer of alpha and beta subunits
- integral protein
- wound healing, embryo attachment..
How is pregnancy establishment proceed?
integrin alpha 6 is involved in the embryo attachment to the uterus (not alpha V beta 3)
Cytosol vs. cytoplasm?
cytoplasm: gel with organelles suspended in cytosol
cytosol: intracell fluid water
What are the two major groups of organells?
membranous: specialized sacs or canals made of the cell membrane (Golgi, ER, plasma membrane, lysosome, proteasome)
non membranous: microscopic filaments and other materials (cytoskeleton, ribosome, cilia, flagella, nucleolus)
What is the structure of the ER?
present throughout the cytoplasm, extends rom the nucleus to the membrane
circulates protein transport form nucleus to cytoplasm to cell surface
What are the 2 types of ER?
smooth: no ribosome, synthesize lipid and carbohydrate, makes membrane, removes Ca+ stores– muscle contraction and hormone production
rough: ribosomes on surface, synthesize proteins, intracellular transportation (to Golgi)
synthesized protein and movement through canals of the ER= fold and assemble into macmolecular groups
What kind of protein does the ER synthesize?
for cell export or cell membrane
