2. Intro to cells, tissues and organs Flashcards
structure of a typical cell:
membrane bound organelles
vesicle golgi mitochondrion SER RER peroxisome lysosome
structure of a typical cell:
cytoskeleton
actin filaments
intermediate filaments
microtubules
centriole
structure of a typical cell:
nucleus
nuclear membrane
nucleus
nucleolus
structure of a typical cell:
cell surface specialisation
cell membrane surface projections surface pit anchoring junction cell surface folds
cells are
fundamental units of life capable of independent existence
fundamentally similar in nature
units of structures as well as activity
cells arise by
division of existing cells
cells can
transform into structures lacking in cellular features (modified cells, cell products)
cells may
vary according to functional dictates (division of function/ labour)
in multicellular organisms
cells are organised into tissues, organs and systems
properties of prokaryotes
- bacteria, mycoplasmas, blue-green algae
0. 1-5 nanometre - allows ions and organic molecules that enter them to quickly spread to other parts of cell
no nucleoli no nuclear envelope no histones few intracellular membranes 60-70s ribosomes
properties of eukaroytes
other algae, fungi, protozoa, multicellular plants and animals
10-100 nanometres- complex organelles and cytoskeleton
prominent nuclear envelope nucleoli DNA complexed with histones many membrane bound organelles 70-80s ribosomes
what are viruses
parasites which lack characteristics so cannot put into classification scheme
Tissue- define
cellular and extracellular matrix (often fibrous) elements in which one or more types of cell or fibre usually predominates to form the material basis of one of the functional systems of the body
embryology define
study of development of fertilised ovum into tissues and organs of the body
The cleavage (cell division) of fertilised ovum transforms it into ball of loosely packed cells- rearrange to form 3 primary germ layers
3 primary germ layers
ectoderm
mesoderm
endoderm
histogenesis
formation of main tissues by cell proliferation and specialisation
organogensis
tissues interact together to form organs
cell differentiation
stable changes of cellular properties which progressively concentrate the activities and structure of the cell, in particular directions at the expense of others
cell proliferation and growth accompanied by cell specialisation
cell differentiation vs modulation
modulation describes minor and reversible changes in cell behaviour
the basis of cell specialisation is
differential gene expression
main process of cell differentiation
gene activation/ repression
ectoderm (6)
nervous tissue lens skin- epidermis linings of oral, nasal, vaginal and anal cavities pituitary gland adrenal medulla
mesoderm (7)
muscle connective tissue skin- dermis blood vessels and lymphatics internal reproductive organs kidneys and ureters adrenal cortex
endoderm
epithelium of pharynx, auditory tubes, tonsils, thyroid and parathyroid, thymus, larynx, trachea, lungs, digestive tract, bladder, urethra and vagina
liver and pancreas
Four primary tissues of the body
- epithelia: sheets of closely packed cells derived from one of three germ layers, cover/ line surface of organ
- connective tissue (support tissue): derived from mesoderm, cells produce EC fibres and an amorphous ground substance
- muscular tissues: large cells, cytoplasm contains filaments made of contractile proteins
- nervous tissues: from neuro-ectoderm
systems of the body
respiratory circulatory digestive (alimentary) reproductive nervous
lysosomal system: lysosome
LYSOSOME: membrane bound vesicle containing digestive enzymes
destroys material from outside within cell
produced from ER and Golgi
destructive enzymes separated from rest of cell by specialised membrane
lysosomal system: peroxisome
special type of lysosome contains catalase
coverts toxic hydrogen peroxide to water
lysosomal system: proteosome
degrades ubiquitinated proteins
