1. Tissue Types and Functions

2. Mammals have four basic types of tissue ◦ Epithelial ◦ Connective ◦ Muscle ◦ Nerve Tissue is a collection of cells, organized for a particular function.

3. Epithelial 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

4. Epithelial Tissue Epithelial 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

5. Epithelial Tissue Epithealial 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

6. Epithelial Tissues Epithelial 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

7. Epithelial Tissues Cuboidal (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

8. Integument Skin 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

9. Muscle Types Three muscle types -skeletal, smooth, and cardiac Skeletal 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

10. 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.

11. Skeletal Muscle A. 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.

12. 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

13. Cardiac Muscle A. 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.

14. Smooth Muscle A. 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.

15. 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.