Ch.5-Tissues Flashcards
List the 4 major types of tissues.
Epithelial
Connective
Muscle
Nervous
Describe Epithelial tissue.
Is an Avascular layer of cells that forms a barrier, providing protection and regulating permeability.
Functions include:
physical protection-eg.skin protects exposed inner surfaces
absorption-eg.intestine takes nutrients from food
filtration-eg.trachea removing particles from air
excretions-eg.skins sweat glands
sensation-eg.tongue has large sensory nerve supply
specialised secretions-eg.gland cells producing enzymes,hormones,etc.
permeability-all substances entering/leaving the body cross an epithelium.
regeneration-environmental factors cause epithelial tissue to reproduce quickly and replace lost cells for as long as they receive enough nutrition.
Covers body surfaces
Cover and line internal organs, and body cavities
Make up the glands
Anchored to connective tissue by a basement membrane
Describe connective tissue.
Cells are farther apart than epithelial tissues
Bind body structures together
Provide support and protection
Create frameworks
Fill body spaces
Store fat for reserve fuel
Insulate the body
Produce blood cells
Transports fluids and dissolved materials
Repair damaged tissues
Protects body from infection
Contain a large amount of ‘matrix’ which is composed of fibers and ground substance
Describe 3 types of muscle tissue and their characteristics.
Can contract by shortening the elongated muscle fibers, this action moves body parts
Skeletal(Voluntary) muscle tissue - found in muscles controlled by conscious effort - attached to bones, composed of long thread-like cells with light and dark markings called striations, these multinucleated muscle cells contract when stimulated by nerve cells - allows all voluntary moves made by head, trunk and limbs
Smooth(Involuntary) muscle tissue - composed of elongated, spindle-shaped cells in muscles not under voluntary control(not controlled by conscious effort), smooth muscle fibers are shorter than striated fibres and have only one nucleus per spindle-shaped fibre - can divide and regenerate after injury - composes hollow internal organ walls such as intestine or bladder, moving food through digestive tract or emptying urinary bladder - tastes completed by contracting or relaxing.
Cardiac muscle tissue(Myocardium) - thick contractile middle layer of heart wall - composed of fibres with characteristic cross-striations of muscular tissue, these striations branch frequently and are interconnected, forming a network. Myocardial muscle contains less connective tissue than skeletal muscle and is usually uninucleate(having a single, centrally located nucleus) - involuntary - makes up most of the heart - relies on pacemaker cells for regular contraction. Cardiac muscle cells are branched and fit together tightly at junctions known as intercalated discs.
Discuss the basic structure and role of neural tissue.
Specialised for conduction of electrical impulses from one region of the body to another
Nervous tissues contain 2 basic types of cells: neurons and several kinds of supporting cells, collectively called neuroglia or glial cells.
Found in brain, peripheral nerves and spinal cord
Basic structure of nervous tissue is the ‘neuron’ that responds to environmental changes by transmitting impulses along ‘axons’(cellular processes) to other neurons, muscles or glands. They respond to stimuli via processes called dendrites.
Neurons coordinate, integrate and regulate a wide variety of functions in the body
Neuroglial cells are crucial to neuronal function, they divide and support nervous tissue components. They also supply nutrients to neurons, and help communicate between cells. 4 types of neuroglia are Astrocytes, Oligodendroglia, microglia, and Ependymal cells.
Discuss types and functions of Epithelial tissue
Simple squamous epithelium - single layer of thin and laterally flattened cells - lines alveoli, forms capillary walls, lines blood and lymph vessels, covers body cavity membranes,
functions - diffusion,filtration, osmosis.
Simple cuboidal epithelium - Single layer of cube shaped cells appearing to be approx. Same height and width - covers ovaries, lines kidney tubules and glandular ducts,
functions - secretion and absorption.
Simple columnar epithelium - consists of cells that are longer than wide, composed of a single cellular layer - found in female reproductive tubes, uterus, and most digestive tract organs,
Functions - secretion, absorption and protection
Pseudostratified columnar epithelium - appear as if they are layered(pseudo), cells vary in shape and usually reach basement membrane, usually have cilia - lines respiratory passages,
functions - movement of mucus, protection and secretion.
Stratified squamous epithelium - Thick layer with cells that flatten as they are pushed outward, it forms the epidermis, with cells hardening as they age(keratinisation) - forms the epidermis and lines the mouth, oesophagus, vagina and anus,
Functions - protection
Stratified cuboidal epithelium - usually 2 but up to 3 layers of cubed cells - lines mammary gland ducts, sweat glands, salivary glands, pancreas, and the developing ovaries and seminiferous tubules,
Functions - protection
Stratified columnar epithelium - several layers of either columnar or cubed shapes, occurs at junctions/transition areas between 2 other types of epithelia- found in the male urethra, ductus deferents, and areas of the pharynx,
Functions - protection and secretion
Transitional epithelium - changes in appearance in response to tension, the cells of its basal layer are columnar or cuboidal, Apical cells have different appearances based on the distension occurring in the organ where they are found, eg. Bladder distension causes it to thin from 6 cell layers to only 3, with the dome-like Apical cells flattening to appear like squamous cells, this transitional ability allows for greater volumes of urine to be stored in the bladder - lines the urinary bladder, ureters, and superior urethra, prevents urinary tract contents from diffusing back into the internal body environment,
Functions - distensibility and protection
Glandular epithelium - consists of specialised cells that produce and secrete substances into ducts or body fluids - usually found in exocrine glands(open onto surfaces surface or into digestive tract) or in endocrine glands(secrete into tissue fluid or blood)
Functions - secretion
Explain fluid connective tissues.
Blood and Lymph are fluid connective tissues that contain distinctive collections of cells in a fluid matrix. They transport materials between interior body cells and other cells that exchange substances with the external environment, so maintaining a stable internal environment.
Blood is formed of several elements(red and white blood cells, and platelets) all suspended in a liquid extracellular matrix known as blood plasma. Most blood cells are formed in the red bone marrow. Red blood cells(erythrocytes) are the most prevalent type of blood cell. Blood is classified as a connective tissue because it develops from mesenchyme.
During blood clotting, the fibers of blood(soluble protein molecules) form visible fibre-like structures.
Lymph forms as interstitial fluid entering the lymphatic vessels, which return the lymph to the cardiovascular system.
Unlike other connective tissues, blood and lymph do not connect structures or provide any mechanical support.
