Diversity of Cells in Tissues and Organs Flashcards
Epithelium
Epithelia cover body surfaces or line hollow organs (i.e. gall bladder) and form many glands
Can also form solid organs such as the liver
Adhesion - strong, sheets of cells with minimum intracellular space
Basal lamina - cells are attached
Polarised - apical and basal ends
Functions:
Mechanical barrier, Chemical barrier, Absorption, Secretion, Containment, Locomotion, Sensation, Contracility
Covering Epithelia
Cell shape
- Squamous (flat), Cuboidal (cube), Columnar (tall and thin)
Number of Layers
- SImple (one), Stratified (two or more), Pseudostratified (one, but looks more)
Cell Surface
- Microvilli (microfilament core), Cilia (microtubule core), Keratinised
Specialised Cell Types
- Goblet cells
Glandular Epithelia
Produce secretory products - i.e. sweat, milk, oil, hormones
Endocrine - secreted towards basal end of cell and distributed via vascular system, ductless, lots of capillaries, i.e. pancreas, anterior pituitary
Exocrine - secreted towards apical end of cell into lumen (duct) or body surface, ducted, i.e. Salivary glands
Connective Tissue
Forms framework of body and has a dynamic role in the development , growth and homeostasis of tissues and in energy storage (fat)
Soft Connective Tissue
Tendons, Ligaments, Mesentery, Stroma of Organs, Skin dermis
Consists of
- ECM - Fibres (collagen, reticular, elastic), Ground substance, tissue fluid
- Cells - FIbroblasts, Adipose cells, osteocytes, chondrocytes
Soft Loose CT
Loosely packed fibres separated by abundant ground substance
Soft Dense CT
Packed bundles of Collagen fibres
Regular - fibres aligned
Irregular - fibre bundles in different directions
Hard Connective Tissue
Strong, flexible, compressible and semi-rigid (GAGs/ proteoglycans)
Avascular - receives nutrients by diffusion through matrix
Hyaline - cartilage matrix, chondrocytes
Elastic
Fibrocartilage
Bone
Cortical Bone - outer dense shell
Trabecular Bone - ends of bones, fine meshwork
Haversian Canals - blood vessels, nerves and osteocytes reside here
Blood and Lymph
Muscle
Specialised to generate force by contracting
3 types:
Skeletal
Cardiac
Smooth
Contractile fibers in cytoplasm
Force produced by actin over myosin movement + accessory proteins
Smooth Muscle
Involuntary - no conscious control
Visceral - mostly in organs
No visible striations
FIbres are elongated, spindle shaped cells
Cigar-shaped nucleus
Skeletal Muscle
Voluntary - conscious control, some are not
Striated muscle
Giant multinucleated, cylindrical cell
Length and diameter varies
Elongated nuclei at periphery of cell (sarcolemma)
Cardiac Muscle
Major part of walls of heart, chambers and origins of great vessels
Striations
Shorter than striated muscle and branch to form networks
Single nucleus in centre of fibre
Intercalated disc - end-to-end attachments between cells (gap junctions, mechanical integrity)
Nervous Tissue
Consists of neurons and supporting cells (glia, far greater number)
Control function and allows for rapid communication between body parts
Surrounded by CT coat
- Meninges = CNS
- Epineurium = PNS
