Four Primary Tissues of the Body
Classification of Epithelia
- number of layers - shape of the cells - special features eg cilia
Cardiac Muscle
continuous rhythmic contractility of the heart have characteristics of both skeletal and smooth muscle long cylindrical cells with one or two nuclei - forms a syncytium
desmosomes
dense regions of attachment between epithelial cells function as an anchor tonofilament bundles insert into each half of the desmosome eg strong bonds in skin cells
adhering junctions
desmosome belt desmosome
Anatomically:
nervous tissue is either CNS or PNS
What is an example of negatively charged tissue?
nucleii of cells
How do epithelial cells attach to one another?
occluding junction adhering junctions communicating junctions
Skeletal Muscle
long multinucleated cells under voluntary control
Smooth muscle
movement of visceral or involuntary muscle (but not cardiac) single nucleus blood vessels, GI, uterus and bladder
What is tissue?
A group of similar cells specialised in a particular way for the performance of a common function
How can we classify nervous tissue
Anatomically and functionally
Components
Cells (fibrocytes/fibroblasts, adipocytes, immune cells) Matrix: fibres (collagen, elastin, ground substance and basement membrane)
belt desmosome
like the desmosome but wont stain with the same intensity
Epithelia
Derived from ectoderm (skin), mesoderm (endothelium and mesothelium) or endoderm (gut lumen) Cover or line all body: Cavities Surfaces Tubes
Functions of Epithelium
Functions as an interface between different biological compartments containment secretion absorption exretion diffusion contractility sensation
Glandular epithelia
aggregates of cells - secrete or excrete material not related to them
Basement membrane
attached to epithelial cell - comprises basal lamina and reticular lamina interface between supporting tissues and epithelial cells sheet like arrangement of proteins eg collagen controls epithelial growth doesn't let downward cell growth allows flow of nutrients and metabolites though
Connective Tissue
cells plus extracellular matrix has a common function
What is an example of positively charged tissue?
collegen or cytoplasm of cells.
4 basic types of tissue
epithelial tissue connective tissue muscle nervous tissue
communicating junctions
gap junction
Dyes for seeing tissues
haematoxylin stains blue negatively charged tissue and eosin stains pink and positively charged tissue
Gap junctions
sites of cell to sell communication
Functionally:
somatic nervous system (voluntary) Autonomic nervous system (involuntary)
What is nervous tissue?
supporting connective tissue capable of analysing stimuli and producing coordinated responses.
Simple epithelia
surface - one layer (one free, apical) and other attached, basal) Can be flat, cuboidal, columnar or pseudostratified join in tight junction
occluding junctions
tight junction
Stratified epithelia
two or more layers of cells squamous transitional
tight junction
usually found closest to the free surface of epithelial cell. consist of two closely apposed cytoplasmic membranes prevents materials leaking fused together but have adjustable permeability present at apices of glandular cells