Primary Tissues Flashcards
(31 cards)
How do the different cell types in the human body arise?
From differential gene expression; most body cells express only a subset of genes, resulting in distinct cell types.
What determines a cell’s structure and function?
Protein expression patterns regulated by transcription factors and DNA modifications.
What are stem cells?
Originator cells (pluripotent in embryos or tissue-specific in adults) that undergo asymmetric division and produce specialised cells.
What is a tissue?
An aggregate of specialised cells designed for a specific function.
What is an organ?
A structure made of multiple tissues performing a coordinated function.
What are the four basic tissue types in the human body?
Epithelial, Nervous, Connective, Muscle
What are the main functions of epithelial tissue?
- Secretion
- absorption
- transportation
- mechanical support
- receptor function
What defines epithelial classification by shape?
Squamous: flat, sheet-like
Cuboidal: cube-like
Columnar: taller than wide
What defines epithelial classification by layering?
- Simple: single layer
- Stratified: multiple layers
- Pseudostratified and transitional are special classifications
What are examples of epithelial surface modifications?
- Microvilli: absorption
- Cilia: movement (motile, sensory, nodal types)
What are the types of epithelial junctions?
- Tight junctions: sealing barriers
- Desmosomes: link intermediate filaments
- Gap junctions: allow passage of small molecules
- Adherens junctions: link actin filaments
What is the basement membrane?
A protein-rich matrix anchoring epithelium, providing strength and linking cells.
What are the structural parts of a neuron?
- Soma (cell body)
- dendrites (input)
- axon (output)
- synapse (transmission site)
How do neurons communicate?
Via electrical signals (action potentials) and neurotransmitter release at synapses
What is myelination?
A fatty sheath around axons; Schwann cells in the PNS, oligodendrocytes in the CNS
What are glial cells?
Supporting cells in the nervous system, 10x more numerous than neurons
What are the types of glial cells?
CNS: Oligodendrocytes, astrocytes, microglia, ependyma
PNS: Schwann cells, satellite cells
What do astrocytes do?
- Provide metabolic
support - maintain ion balance
- regulate synapses
- form glial scars
What do microglia do?
Act as brain’s immune cells and phagocytes
What are the three muscle types?
Skeletal, Cardiac, Smooth
What are skeletal muscle features?
- Striated
- multinucleated,
- voluntary control
- contains sarcomeres
What are cardiac muscle features?
- Striated
- Branched
- Involuntary
- Gap junctions
- Adhering junctions
What are smooth muscle features
- Non- striated
- Spindle - shaped cells
- Involuntary
- No regular filament arrays
What are the main components of connective tissue?
Various cells + extracellular matrix (ECM)
