1. Tissues

2. Tissue is…. A collection of cells organized for a particular function
Collections of tissue are then arranged into organs

3. Tissue types Mammals have 4 basic tissue types Epithelial Connective
Muscle
Nerve

4. Epithelial Tissue Collections of cells packed together is sheets
They lie the body’s surface and openings
They also cover the openings of the
Intestinal tract
Reproductive tract
Urinary tract
They line the tubes in the body such as blood vessels and heart

5. Epithelial functions Functions of epithelial 1. Defense 2. Secretions
Skin, respiratory tract
2. Secretions
Tears and saliva help to moisten the tissue
Urine and sweat
Milk from mammary

6. Functions of Epithelial
3. Absorption
Very highly selective
Intestines, lungs and kidneys absorb from surrounding fluid
Cells lining the blood vessels provide point of exchange for materials in the blood and ECF
4. Conserve materials
Prevent excess loss of fluid and nutrients from the ECF

7. Epithelial
Every epithelial tissue (ept tissue) has an underlying connective tissue layer
 > Ept tissue has no direct blood flow so the connective tissues provide
1. Support
2. Nutrients
3. Removes waste

8. Classifications of Epithelial
1. Simple
One cell layer 
2. Stratified
Multiple layers 
3. Transitional
Multiple layers with the shape of the cell changing

9. Shape of cells 1. Squamous 2. Cuboidal 3. Columnar Very flat
Cube shaped 
3. Columnar
Taller than they are wide
The 2 most appropriate terms are combined to describe the tissue

10. Cell shapes Simple squamous epithelium Single layer of flat cells
Located where there is need for exchange
Ex: blood vessels are lined with it for transfer of fluids, nutrients and gases and wastes

11. Cell shape Simple cuboidal Ept
Single layer of cells that are almost square
Located in many glands and tubules of the kidneys
Functions – secretions or absorption

12. Cell Shapes Simple columnar ept
A single layer of cells that are taller than wide
Located in glands, stomach and intestines
Stratified cuboidial and columnar also exist in certain glands and ducts
Stratified squamous ept
Ex: skin

13. Cell shapes Transitional Ept Specific to urinary tract only
It can be stretched
Relaxed it looks several layers thick
As bladder fills, stretches, when full it seems on a few cells thick
It also can prevent exchange of fluid between urine and underlying tissue

14. 2 way barrier over the body Functions
Integument
Also called skin
2 way barrier over the body
Functions
Damaging agents are kept out
Fluid and nutrients are kept in

15. Specialized skin cells
Hair, fur and sweat glands
Help maintain stable body temp
Pigment
Protects body from UV radiation
Clinically the skin is the first impression of an animals overall health. Many diseases appear on the skin – fleas, hair loss and skin sores
Parasitic, nutritional and endocrine diseases affect the skin

16. Skin Skin – 2 layers 1. Epidermis 2. Underlying dermis Epidermis
Epidermis
Stratifies squamous ept
Originated from the basal layer and move outward and shed from the surface
Dermis
Connective tissue layer that contains
Blood vessels
Nerves
Glands

17. skin Hypodermis 2nd layer of connective tissue
Supports the skin (epidermis with dermis)
Hypo = beneath

18. Specialized skin cells
The footpads/digital pads of dogs and cats are specialized skin cells
Thickened layer
Resist physical trauma
A pad of fat is under this to act as a cushion

19. Hair Is a Modification of epidermal cells Functions 1. Insulation
Functions
1. Insulation
2. Protection
3. Sensation

20. Hair Originates from the follicle in the dermis
Hair shaft is made of Ept cells
Growth occurs as cells are attached to the base of the hair

21. Arrector Pili
Muscle that is attached to the connective tissue around the hair follicle
Contracted = the hair stands upright
Cold weather improves insulation effect of the hair.

22. Claws and hooves
- Modified epidermis

23. Keratin A specialized protein that is deposited in the cells
Gives hardness and durability
The claws of dogs and cats surround the last bone of the toe
Hooves are similar to claws
The last bone of the equine foot is suspended within the hoof

24. Laminar Corium
Supports and nourishes the hoof wall
Is connective tissue
Growth of the hoof
Occurs in the coronary band when cells are deposited

25. Horns The same as hoof and claw
The center of the horn is a bone that surrounding tissues supplies blood to feed
Horn material is called keratinized epithelium

26. Muscle tissue 3 muscle types exist in mammals - Skeletal - Smooth
3 muscle types exist in mammals
- Skeletal
- Smooth
- Cardiac

27. Skeletal Attaches to the skeleton Allows for motion
Under voluntary control
Animals move with nerve signals

28. Smooth Muscle Involuntary muscle
Located in many hollow organs of the body
Ex: blood vessels
Gastrointestinal tract
- Urinary bladder

29. Cardiac muscle Located in the heart Involuntary
Skeletal muscle is striated voluntary muscle 
A muscle consists of thousands of muscle fibers or muscle cells

30. Myofiber An entire muscle cell Have several nuclei
Lots of mitochondria
Organized in parallel rows
Separated by connective tissue that includes blood vessels and nerves

31. The ability of a muscle fiber to contract is a very complicated system
Within the fiber – an organized system of myofilaments exist

32. 2 proteins make up the filaments
Actin
Myosin
They are all organized along the length of the cell

33. During contraction the actin and myosin filaments slide along each other
The filaments have small bridges between them that bind and release as they slide
The contraction starts originally with the stimulation from a nerve cell

34. The stimulation releases calcium stored in the endoplasmic reticulum
This flow of calcium ions causes the filaments to slide across each other
A large amount of mitochondria are present to provide energy. 
During relaxation, the cell will actively transport calcium back to the endoplasmic reticulum

35. Porcine Stress Syndrome (PSS)
Genetically transmitted disease in which the calcium is not transported back to the endoplasmic reticulum
This causes muscles not to relax
Occurs when pigs are stressed for heat or transportation

36. Rigor Mortis Muscle stiffness
Occurs at death because there is no energy to pump the calcium back to the endoplasmic reticulum
With energy, muscles can not relax

37. Hypocalcemia
Dairy cattle develop a lack of calcium around calving time
The cow drastically increases calcium for mild production
So much calcium is excreted in the mild that the levels on the blood and muscles becomes too low
The cow becomes weak and unable to stand

38. Hypocalcemia Treatment
Calcium solution placed directly into the bloodstream
Within minutes the cow can stand
Muscles will grow or shrink based on usage and nerve damage

39. Sweeny
Damage to the shoulder nerve in a draft horse causing the muscle to shrink

40. Cardiac Muscle Striated and involuntary
Myofilaments look the same as skeletal and contraction procedure is the same
No nerve stimulation is necessary for contractions
Specialized pacemaker cells are responsible for the rate of contraction

41. Cardiac
Nerve cells are present to help influence the rate of contraction
The automatic nervous system can increase or decrease the rate
As long as there is oxygen and glucose provided to the muscle cells – the heart beats

42. Smooth Lacks striation
Contains actin and myosin filaments but not in the same arrangement
Each myofiber is spindle shaped and tapered at each end
Each cell has only one nucleus

43. Smooth Muscle Arranged in sheets around hollow openings
Contraction makes opening smaller
Example: contraction in blood vessels
Contract much slower than skeletal muscle
Maintain the contraction longer
Controlled by the automatic nervous system

44. Nerve Tissue Allows communication among areas of the body
Located in brain and spinal cord
Brain and spinal cord together is called the central nervous system

45. Peripheral Nervous System
Nerves located outside of brain and spinal cord

46. Neurons Cells in nerve tissue Large
Body of it holds the nucleus and other organelles

47. Axon A hair like extension from the cell body Carries nerve impulses
Can end on either tissues or other neurons
Axons from many neurons bundle together to form a nerve
Can be very long
Example: horse – can be 2 meters long

48. Dendrites Other extensions of the neuron
Axon often ends on a dendrite of another neuron
The site of this connection is called a synapse
When stimulated, the dendrite begins the nerve impulse

49. How nerve impulses happen
Flow of ions passes through cell membrane
In a resting nerve cell – sodium ions are actively transported into extra cellular fluid
At the same time, potassium is pumped into the cytoplasm
Stimulation causes ions to flow across the cell membrane
Stimulation moves down the axon quickly

50. Nerve impulses can be measured as an electrical event in the body

51. 3 types of neurons 1. Sensory neurons
Have receptors that stimulate in response to an animals change in environment
Receptor types
Light, heat, touch hearing, balance, taste or smell

52. 2. Interneuron
Found within the central nervous system
Stimulated by a sensory neuron
Allows a pathway that lets the central nervous system control the animals activities

53. 3. Motor Neurons
Begin at central nervous system and extend to a muscle or glands
When stimulated – an action occurs
Example: muscle contracts = gland secrets
Stimulation occurs by a sensory neuron or an interneuron.