Tissues Flashcards
Learning Objectives
Name the four basic tissue types
Identify & describe the structure, location & function of the different types of tissues
Relate tissue structure to function.
Epithelial Tissue Functions
- Covers body surfaces, lines cavities and forms glands
- Physical Protection - mechanical & chemical
- Regulate the movement of substances into and out of the body
- Secretion - glands are epithelial
- Sensory perception richly innervated (e.g. touch receptors in skin)
Epithelial Tissue Structure
Cells are close together Avascular (no blood vessels) Structural + functional polarity Regenerative Attaches to connective tissue
Classification of Epithelial Tissue
# of layer of cells - simple or stratified - psuedostratified is rarer, not really stratified SURFACE cell shape - squamous (flat) - cuboidal (square) - columnar (column shaped) Any specialisations
Epithelial Glands
Exocrine - release secretions onto epithelial surface either on epithelial surface or connected by a duct, e.g. sweat, salivary, lacrimal glands, oil glands
Endocrine - lack ducts release secretions (hormones) into the interstitial fluid or the bloodstream e.g pituitary gland, thyroid gland
Connective Tissue Functions
- Support - structural and chemical
- Protection
- Surround and interconnect other tissue types
- Transport of fluids
- Energy storage
- Immune defence
Connective Tissue Structure
Cells and Extensive Extracellular Matrix (ECM)
Not exposed to the external environment as it is located beneath the epithelia
All connective tissues consist of:
1. Specific cells, protein fibres, ground substance (last two are ECM)
2. Can be classified on basis of cell type and composition of ECM
Connective Tissue Classifications
- Connective Tissue Proper
- Loose (areolar, adipose, reticular) or Dense (regular, irregular, elastic) - Supporting Connective Tissue
- Cartilage (hyaline, elastic, fibrocartilage) or bone (compact, spongy) - Fluid Connective Tissues
- Blood or lymph
Supportive Connective Tissue (cartilage)
Cartilage
- Growth can be appositional (widthwise) vs. Interstitial (lengthwise)
- Supportive but can withstand some deformation
- Chondrocytes sit in lacunae
- Extracellular matric (around 95%)
- fibres
- ground substance
3 fibre types:
1. Hyaline (most common, scattered chondrocytes + perichondrium)
2. Fibrocartilage (extreme durability, parallel rows of chondrocytes and fibroblasts, no perichondrium)
3. Elastic (resilient and flexible, elastic fibres, perichondrium)
Supportive Connective Tissue (Bone)
Osteocytes sit in lacunae
ECM - type I collagen, ground substance is mineralised (calcium salts)
Surrounded by a periosteum
Dense Regular Connective Tissue
extracellular fibres take up most of the volume and cells are fibroblasts
provides firm attachment, conducts pull of muscles, reduces friction between muscles; stabilises relative positions of bones
Typical Long Bone Parts
Epiphysis, metaphysis, diaphysis, metaphysis, epiphysis
Muscle Tissue Functions
Specialised for contraction
- movement and support of body parts
- movement of material through the body
- temperature regulation
- myocytes contain intracellular proteins of actin and myosin
Muscle Tissue Functions
Specialised for contraction
- movement and support of body parts
- movement of material through the body
- temperature regulation
- myocytes contain intracellular proteins of actin and myosin
Types of Muscle Tissue
Cardiac
- involuntary and has striated, branched, uninucleated fibers
Smooth
- spindle-shaped, nonstriated, uninucleated fibers
occurs in walls of internal organs and is involuntary
Skeletal
- striated, tubular, multinucleated fibers, voluntary, usually attached to skeleton
