Tissues 1 Flashcards
What is the body composed of?
Cells grouped into tissues and organs
Cells - Tissues - Organs - Systems - Organism
What are the 4 basic types of tissues?
Epthelia
Connective
Muscle
Nervous
What is connective tissue?
Tissue which provides general structure, mechanical strength, space filling and physical and metabolic support for tissues
What are the 3 structural properties of connective tissues?
Tensile strength
Elasticity
Volume
What gives connective tissues their tensile strength?
Strong fibres of stuctural proteins from the collagen family
What gives connective tissues there elasticity?
Elastin fibres allowing it to return to its original shape
What gives connective tissues there volume?
Glycoproteins and complex carbohydrates forming the gound substance
What is the extracellular matrix (ECM)?
Combined mix of fibres and ground substance
What are 3 examples of connective tissue?
Blood
Bone
Adipose
What is the dominant function of muscle tissue?
To generate force through contraction
What are some properties of muscle tissues?
Contractile
Long thin cells
Cytoplasm packed with contractile apparatus
Shortens lenth, closing down spaces
What are the 3 forms of muscle tissue?
Skeletal muscle (voluntary movement)
Smooth muscle (involuntary movement)
Cardiac muscle (contractility of the heart)
What are key features of skeletal muscle?
Large, elongated cells, may be up to 1m
Multiple peripherally situated nuclei
Voluntary muscle
Arrange in fascicles with endomysium, perimysium and epimysium
Cross striations due to organisation of myofibrils
Sliding filament mechanism of contraction
What are key features of smooth muscle?
Small cells
Single central nucleus
Involuntary movement
Surrounded by network of collagen
No stiations
Cells shorten and broaden on contraction
What are key features of cardiac muscle?
Elongated branched cells joined by intercalated disks
Single central nucleus
Involuntary muscle
Branching interconnected cells
Cross striations due to myofibrils
Sliding filament mechanism of contraction
What are the functions of nervous tissue?
Communication
Integrate information
Recieve, generate and transmit electrical signals
What is nervous tissue composed of?
Neurons and glia
What are neurons?
Cells that carry electrical impulses
What is glia?
Provide support and protection for neurons
What does epithelium do?
Lines the outer surfaces of organs and bood vessels, as well as any inner surfaces
What are functions of epithelial tissues?
Covers surfaces
Seperates compartments
What is endothelium?
Cells that line the interior surface of blood vessels
What specialised structures do the plasma membrane of epithelial cells exhibit to allow them to perform their function?
Intercellular surfaces (cell junctions)
Luminal surfaces (celia, microvilli or sterocilia)
Basal surfaces (connects to underlying connective tissue, basement membrane)
What does the basal structure do?
Connects to underlying connective tissue
What are the 3 different types of cell junctions?
Desmosomes (also called adhering junctions)
Tight junctions
Gap junctions
What do desmosome junctions do?
Provide anchoring points for cytoskeletons by using transmembrane proteins
Where are desmosome junctions often found?
In tissues that experience mechanical stress such as cardiac muscle and bladder tissue
What do tight junctions do?
Seal interceullular space to block the passage of contents between cells
Where are tight junctions found?
In the intestine and the stomach
What do gap junctions do?
Allow cell to cell communication using transmembrane channels
Where are gap junctions found?
Cardiac muscle and nerves
What kinds of tissues are junctions found in?
All 4, epithelium, muscle, nervous and connective
What is the basement membrane?
Connects epithelial tissue to connective tissues, providing structural support and passage of materials
What is the basement membrane composed of?
Basal lamina
Reticular lamina
What is the basal lamina?
Secreted by epithelial cells, on which they sit
What is the reticular lamina?
Connects basal lamina to underlying connective tissue
What are some examples of ECM junctions?
Hemidesmosomes (epidermis of skin)
Skin basal lamina
BV endothelium
What are some secondary functions of epithelium?
Wear and tear (thick)
Diffusion (thin)
Movement
Absorption
What are celium?
Finger like projections from apical surfaces that beat to move particles
Where is celium found?
Trachea
What is microvilli?
Finger like projections that increase the surface area to better allow absorption
Where is microvilli found?
Small intestine
What is epithelium classified by?
The number of cell layers
What are the 2 classes of epithelium?
Simple (one layer)
Stratified (muliple layers)
What can simple epithelial be?
Squamous (vascular endothelium)
Cuboidal (collecting tubule of kidney)
Columnar (small intestine)
What can stratified epithelium be?
Squamous (epidermis of skin)
Cuboidal (exocrine gland ducts)
Columnar (urethra)
Transitional (bladder)
Where is the only place transitional epithelium can be found?
In the urine tract to combat the toxicity of urine
What is pseudostratified columnar epithelium?
Simple (all cells attatched to basement membrane) but stratified due to nuclei being at different points
Where is pseudostratified columnar epithelium found?
Trachea
