Chapter 5 - Tissues Flashcards
what creates tissue
cells. The combination of different cell types, with similar structures and functions, creates tissue.
The four basic tissue types
epithelial
connective
nervous
muscle
describe: Epithelial tissue
epithelia and glands: covers the surface of the skin and organs forms the inner lining of body cavities lines hollow organs makes up glands
anchored to connective tissue by a ‘basement membrane’
classified according to shape of their cells and number of cell layers
describe: Connective tissue
widely distributed throughout the body, filling internal spaces. Binds, Supports and protects body structures.
describe: Nervous tissue
carry information from one part of the body to another via electrical impulses. found in:
the brain and spinal cord (CNS)
the nerves (PNS)
describe: Muscle tissue
specialised for contraction and include
skeletal muscles(attached to bones, used for movement of the body)
the heart
muscular walls of hollow organs
cardiac (involuntary)
smooth ( involuntary)
Striated (voluntary)
describe: Epithelium
an avascular layer of cells that forms a barrier, providing protection and regulating permeability.
describe: Glands
are secretory structures derived from epithelia
functions of Epithelia - physical protection
abrasion, dehydration, destruction from biologic or chemical agents.
Tightly interlocked epithelial cells of the circulatory system reduce friction between the blood and the walls of the blood vessels.
functions of Epithelia - Absorption
examples of epithelia that absorb or secrete substances are those that line the kidney tubules and intestine. In the intestine certain epithelia absorb nutrients from the digestion of food.
functions of Epithelia - Filtration
Some epithelia have tiny motile cilia that propel substance along free surfaces, as part of filtration. These include epithelia lining the trachea and other air passages.
A thin supporting sheet adjacent to the basal surface of an epithelium is called the ‘basal lamina’, which acts as a selective filter. It determines which molecules can diffuse from underlying connective tissue can enter the epithelium.
functions of Epithelia - Excretion
In the kidneys epithelia excrete waste products and also reabsorb needed material form the urine.
In the skin, the epithelia of sweat glands excrete sweat.
functions of Epithelia - Sensation
Most epithelia are very sensitive to stimulation because they have a large sensory nerve supply. Sensory stimuli penetrate specialised epithelia. Such tissue is found in the eyes, ears, skin, nose and on the tongue.
functions of Epithelia - Specialised secretions
Epithelial cells that produce secretions are called gland cells. Cells of this type are scattered among other cells in an epithelium. Most or all of the epithelial cells in a glandular epithelium produce secretions, which are either discharged onto the surface of the epithelium or released into the surrounding interstitial fluid and blood. These secretions include enzymes, hormones and lubricating fluids.
functions of Epithelia - Permeability
Any substance entering or leaving the body must cross and epithelium, so the epithelia control permeability. Some epithelia are relatively impermeable, whereas others are crossed easily by compounds of various sizes. In response to stimuli, the epithelial barrier may be modified and regulated. Hormones can effect ion and nutrient transport through epithelial cells. Physical stress can also alter the structure and properties of epithelia. An example is the formation of calluses on the hands after repeated manual labour.
functions of Epithelia - Regeneration
Epithelia have a strong ability to regenerate because they are often exposed to friction, acids, bacteria, smoke and other environmental substances or factors. They begin to reproduce quickly when their apical-basal polarity and lateral contacts are destroyed. Epithelia can replace lost cells (due to cell division) for as long as they receive enough nutrition.
the 8 functions of epithelia
physical protection absorption filtration excretion sensation specialised secretions permeability regeneration
variations of epithelium cells
squamous
cuboidal
columnar
simple (one layer)
Stratified (multiple layers)
psuedostratified (looks like multiple layers but all cells connect to base - only columnar)
glands - transitional. endocrine, exocrine (compound or simple)
what is fluid connective tissue
a distinctive population of cells suspended in a water matrix. This contains dissolved proteins.
They transport materials between interior body cells and other cells that exchange substances with the external environment, maintaining a stable internal environment.
Name the two type of fluid connective tissue
Blood
Lymph
What formed elements does blood contain
Red blood cells
White blood cells
Platelets
these are suspended in a liquid extracellular matrix known as blood plasma.
Lymph
Lymph forms as interstitial fluid entering the lymphatic vessels, which return the lymph to the cardiovascular system.
what is blood
the formed elements (red blood cells, white blood cells and platelets) and blood plasma make up blood.
what are the three types of muscle tissue
Skeletal muscle tissue
Smooth muscle tissue
Cardiac muscle tissue
characteristics of Skeletal Muscle Tissue
known as voluntary muscle tissue as it is controlled by conscious effort, contracting when stimulated by nerve cells.
attaches to bones.
composed of long thread like cells that have light and dark markings called striations.
The cells are multi nucleated.
Skeletal muscle cells are also called ‘muscle fibers’.
Long and cylindrical containing many peripherally located nuclei.
characteristics of Smooth Muscle Tissue
Composed of elongated, spindle shaped cells in muscles not under voluntary control.
shorter then striated fibers.
one nucleus per spindle shaped fiber.
also called ; ‘non-striated involuntary muscles’ or ‘unstriated muscles’.
they can divide, regenerating after being injured.
composes hollow internal organ walls (intestines, stomach, bladder, blood vessels, uterus)
cannot be controlled by conscious effort.
moves food through the digestive tract, empties the bladder and constricts blood vessels by contracting or relaxing.
characteristics of Cardiac Muscle tissue
also called ‘myocardium’
thick contractile middle layer of the heart wall.
Composed of fibers with cross striations, branching frequently and are interconnected, forming a network.
Contains less connective tissue then skeletal muscle and is usually uninucleated.
Its involuntary and 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.
basic structure of neural tissue
Nervous tissues contain two basic types of cells:
1. Neurons
and several kinds of supporting cells, collectively called:
2. Neuroglia or Glial cells
role of Neural Tissue
specialised for the conduction of electrical impulses from one region of the body to another.
Neurons transmit impulses along axons to other Neurons, muscles or glands.
They respond to stimuli via processes called dendrites.
Neurons co-ordinate, integrate and regulate a wide variety of functions in the body.
where do you find nervous tissue
Brain
Peripheral nerves
Spinal chord
role of Neuroglial cells
crucial to neuronal functioning. These cells divide and support nervous tissue components.
Neuroglial cells also phagocytise other cells, supply nutrients to neurons and help in communications between cells.
four types of neuroglia cells
astrocytes
oligodendroglia
microglia
ependymal
