Cellular physiology II Flashcards
nervous tissue structure
composed of neurons
(1 axon, many dendrites, 1 cell body) and glial cells
- oligodendrocytes (CNS)
- schwann cells (PNS)
- astrocytes
- microglial cells
- ependymal cells
- satellite cells (PNS)
nervous tissue function
communication by electrical and chemical signals
neurons: respond to stimuli, transmit a signal
glial cells: assist and protect neurons
muscular tissue
made up of contractile cells
cardiac muscle
skeletal muscle
smooth muscle
epithelial tissue classification
classified into cell shapes and layer types
squamous, cuboidal, columnar
simple, striated, pseudostriated
make up coverings, linings, glands
simple epithelial tissue structure and function
1 layer of cells, good for absorption and gas exchange
squamous - filtration, diffusion, absorption eg alveoli
cuboidal - absorption secretion eg ducts of glands, kidneys
columnar - absorption secretion eg villi, uterus
striated epithelial tissue structure and function
many layers of cells, good for secretion and lining protection
squamous - mechanical protection eg mouth vagina
cuboidal and columnar- protection/secretion eg ducts of glands
other epithelial tissue structure and function
transitional - stretchy eg urethra and bladder
pseudostriated - mucus secretion, have cilia
connective tissue structure
made up of cells and extracellular matrix
extracellular matrix is made up of protein fibres and ground substance
protein fibres are either collagen (strong) or elastin (elastic)
ratio of ground subtsance to protein fibres indicates structure and function
connective tissue proper, supporting connective tissue, fluid connective tissue
connective tissue proper
LOOSE: more ground substance - softer
eg adipose tissue
DENSE: more protein fibres - more tough
eg tendons
supporting connective tissue
firm semisolid matrix: cartilage - either has more elastin to be more elastic or collagen to be stronger
bone - rigid calcified matrix, very strong
fluid connective tissue
eg blood, 45% cells, 55% plasma (ground substance)
tight junction structure and function
cell adhesion proteins called claudin
held together by the plasma membrane
does not allow substances to pass in between the cells, must pass through the cells
not strong
eg blood brain barrier
desmosome structure and function
holds 2 cells together by cytoskeleton (intermediate filaments) with cadherin proteins
very strong, not tight
hemidesmosome anchors cell to underlying basement membrane
prevent epithelium from being peeled away from underlying tissues eg epidermis
gap junctions structure and function and communication
connexon rings made of 6 connexin proteins, spans across 2 plasma membranes, creating a pore
2 cells share cytoplasm, communication between cells, allows solutes to pass through the pore
good for cardiac cells, allows electrical excitation to pass through all the cells at once, beat in unison (no ligand or receptor)
how do communication between cells differ
distance and medium of communication
direct vs indirect (physical contact)
juxtacrine
ligand is on the plasma membrane (transmembrabe proteins or phospholipids) of one cell, receptor is on the plasma membrane of the other cell, requires physical contact between cells, ligand cannot diffuse away
autocrine communication
receptor is transmembrane proteins/phospholipids, on the same cell
ligand travels through extracellular fluid for about 20µm
paracrine communication
similar to autocrine, but 2 different cells
endocrine communication
hormones, long distances, bloodstream
neural transmission
electrical transmission to a specific target organ which are other nerve, muscle or gland
ATP regulated neurotransmitters at synapse
