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Flashcards in Cells and Tissues Deck (14)
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What is a tissue and the 4 primary types

- Tissue: A group of similar cells and their intercellular substance specialised to perform a specific function
- Types: Epithelial, muscle, connective and nervous


What are the characteristics, function and classification of epithelial tissue

- Outer surface of skin, covers open cavities / walls of internal organs, have polarity
- Avascular, nourished by connective tissue, highly innervated / regenerative capacity
- Basement Membrane: Made of collagen / glycoproteins, anchors epithelium, organised scaffold, stains pink (H&E)
- Secretion, barrier, absorption, protection, transcellular transport, sensing and cover
- Layers (simple, pseudo stratified, stratified)
- Shape (squamous, cuboidal, columnar)
- Specialisations (cilia, microvilli, keratin), location of nucleus / basement membrane


What is the difference between cilia and microvilli

- Cilia: 10um long, 0.2um diameter, microtubules, 9 + 2 structure, basal body anchors microtubules, movement of substances along surface, mucous cells near
- Microvilli: About 1um length, 90nm diameter, projections of plasma membrane, bundles of parallel actin filaments, increase SA for absorption


What is keratin

- Main protein on apical surface of your skin and makes hair and nails
- Extremely insoluble in water, protection and barrier, desmosomes


What are the characteristics of muscle tissue

- Movement by contraction, myo-filaments (actin and myosin)
- Highly vascularised / cellular, many mitochondria, specialised cells, long thin cells


What are the 3 types of muscle tissue

- Skeletal: Voluntary, attached to bones, long cylindrical, stripes, striated, multi nucleated near membrane
- Smooth: Involuntary, fusiform, central nucleus, walls of hollow organs, long tapered cells
- Cardiac: Involuntary, composes walls of heart, striated / branched cells, uninucleate, intercalated discs


What are the characteristics of connective tissue and ECM

- Most abundant, support / communication, insulation, protection, nutrient storage
- Connective tissue (loose or dense regular / irregular)
- Cartilage (hyaline, elastic and fibrocartilage)
- Bone and blood
- ECM: Fibres embedded in ground substance (tissue fluid), scaffold between cells, biochemical support to the surrounding cells


Briefly describe how to identify types of connective tissue

- Dense regular: Parallel collagen fibres, fibroblasts
- Dense irregular: Irregularly arranged collagen fibres, fibroblasts
- Loose: Gel like matrix, multiple cells, mesh like structure, branching
- Hyaline Cartilage: Bubbles in glass (chondrocytes), surrounded by matrix
- Elastic Cartilage: Butterfly wings, irregular, multiple cell types
- Bone: Thin layers, concentric / circumferential
- Spongy Bone: Irregular osteons, white spaces surrounded by ECM
- Blood: RBC / WBC
- Adipose: White bubbles, sparse, adipocytes, peripheral nucleus


What are the characteristics of nervous tissue

- Function: Highly specialised to carry electrical signals (waves of membrane depolarisation), generate and conduct nerve impulses, important for communication and control, highly cellular
- Classification: CNS (brain and spinal cord) and PNS (ganglia)
- Neurons: Excitable cells that transmit electrical signals
- Glial: Supporting cells (oligodendrocytes and astrocytes)


Describe the structure and function of veins

- Vein walls thinner than walls of arteries
- Have valves, diameter is larger than of arteries
- Layering in the wall of veins is not very distinct compared to arteries


Describe the structure and function of arteries

- Walls of arteries thick and compact
- Smooth muscle cell nuclei are frequent in the tunica media
- Collagen fibres and a few connective tissue cell nuclei are visible in tunica adventitia


Describe the structure and function of capillaries

- Very small vessels (diameter 4-15 µm)
- Low BF and large SA, provide nutrients and oxygen to surrounding tissue
- Absorption of nutrients, waste products, CO2 and excretion of waste products


Describe the structure of specialised structures (arteries / veins)

- Tunica adventitia (outer connective tissue with collagen fibres)
- Tunica media (middle circularly arranged smooth muscle / elastic fibres)
- Tunica intima (inner specialised simple squamous epithelium)


What are the two types of cuts possible in a specimen

- Transverse: Inner layer of smooth muscle tissue (shape of cells, nuclei location)
- Longitudinal: Outer layer of smooth muscle tissue (striations / intercalated discs, nuclei location)