Tissue Types and Tissue Types and FunctionsFunctions

Mammals have four basic types of tissue◦Epithelial◦Connective◦Muscle◦Nerve

Tissue is a collection of cells, organized for a particular function.

Epithelial TissueEpithelial Tissue• Epithelial tissues are packed

together in sheets.–Line the body’s surface and

openings.• Perform many functions–Offers the body a defense• Trauma• Sun• Extreme temperatures• Drying• Bacterial invasion

Epithelial TissueEpithelial TissueEpithelial cells that line the

respiratory tract, intestinal tract, urinary and reproductive tracts also provide protection.◦Respiratory – cilla

Epithelial cells provide secretions◦Tears, saliva, mucus, urine, sweat,

and milk

Epithelial TissueEpithelial TissueEpithealial cells can also absorb

materials.◦Intestines, lungs, kidneys all absorb

materials from the surroinding fluids.

Epithelium has no direct blood supply.◦Connective tissue provides support,

nutrition, and removes waste via the ECF

Epithelial TissuesEpithelial TissuesEpithelial tissues are classified based on

their shape.◦Simple with one cell layer◦Stratified with multiple layers◦Transitional with multiple layers

There are also descriptive terms for the shape◦Squamous (very flat)

Found where there is a need for exchange Blood vessels Respiratory system lining

Epithelial TissuesEpithelial TissuesCuboidal (cube shaped)

◦Associated with secretion or absorption Glands and tubules in the kidneys

Columnar (more tall than wide)◦Associated with secretion or

absorption Glands, stomach and intestines

IntegumentIntegumentSkin performs a variety of

functions◦Keeps damaging agents out of the

body◦Keeps fluids and nutrients in the body◦Specialization of the skin (hair, fur)

helps to maintain body temperature.◦Detects pain, pressure, and

temperature Sensory organ

Muscle TypesThree muscle types

-skeletal, smooth, and cardiacSkeletal Muscle

-muscle that is attached to the skeletal structure

-voluntary control through nerve signals from the nervous system.

Smooth Muscle-located in many of the hollow organs of the

body, including the GI tract, urinary bladder, blood vessels.

-Involuntary muscle

4. Cardiac Muscle-found in the heart-Involuntary muscle

5. Involuntary muscles- function at all times even when

the animal is asleep.6. Voluntary muscles- function when an animal wants to

move.

Skeletal MuscleSkeletal MuscleA. Formation

-striated voluntary muscle-muscle consists of thousands of muscle fibers (muscle cells)-entire muscle cell is called a myofiber

B. Myofiber-myofibers have several nuclei and large mitochondria.-organized in parallel rows-separated by connective tissue that includes blood vessels and nerves.

C. Myofilaments-made up of two proteins, actin and myosin-organized at entire length of muscle cell-contraction happens when the actin and myosin filaments slide along each other-contraction of muscle fibers begin with stimulation from a nerve cell.-Impulses stimulate the release of calcium (stored in endoplasmic reticulum)-Energy is needed for this process-once relaxed, the cell transports calcium back into the ER

Muscle

Cardiac MuscleCardiac MuscleA. Formation

-striated, but is involuntary in action.-appearance of cardiac myofilaments is very similar to skeletal muscle

B. Function-mechanism is also very similar to the skeletal system, but contain more mitochondria.-muscle contracts on own, but nerve cells help establish rate of contraction.-glucose and oxygen need to be present in order for the heart to beat-Cells are very organized in the action of the heart beating. Electrical signals are sent between cells which allows the heart to function as one unit.

Smooth MuscleSmooth MuscleA. Formation

-lacks striated appearance-still contains actin and myosin filaments, but are not arranged the same as the skeletal muscle.-individual myfibers is a spindle-shaped cell, tapered at each end, with one nucleus.-arranged in sheets around hollow openings like the GI tract.

B. Function-contractions may make openings smaller-in blood vessels it is called constriction-in an organ (esophagus) the contraction helps in propelling food toward the stomach. (peristalsis)-automatic nervous system controls the action of smooth muscle.

Porcine Stress Syndrome◦Disease in pigs where calcium is not transported

back to the ER. Muscles are left stiff.Rigor Mortis

◦Occurs after death because there is no energy to transport calcium back to the ER.

Hypocalcemia (Milk Fever)◦Due to a lack of calcium before calving, causes

weakness…cow can’t stand. Cured by administration of calcium solution to the bloodstream.