1. Equine SCI 2 – Unit 3
Objective 3.01: Understand body surfaces, systems, and how they function

2. Four Basic Surfaces Dorsal: Upper surfaces of the animal
Ventral: Lower (abdominal) area of the animal
Anterior (Cranial): Head (front part) of the animal
Posterior (Caudal): Tail (rear part) of the animal

3. Body systems
Skeletal System: Made up of bone and cartilage that give the body shape and protect internal organs
Muscular System: Provides movement both externally and internally
Digestive System: Converts feed into a form that can be used by the body for maintenance, growth, and reproduction
Urinary System: Maintains water and mineral balance while holding and excreting wastes when needful

4. Body systems
Respiratory System: Takes in oxygen and delivers it to the tissues and cells and picks up carbon dioxide from the tissues and cells to deliver to the environment

5. Body systems Circulatory System: Distributes blood throughout the body
Nervous System: Supplies the body with information about its internal and external environment through electrical impulse between the brain, spinal cord, and others parts of the body

6. Body systems
Reproductive System: Contains the organs necessary for the creating of new organisms
Endocrine System: Produces hormones that influence vital functions

7. Two Main Divisions plus articulations
Skeletal system
The skeletal systems has:
Two Main Divisions plus articulations

8. Skeletal system Axial Skeleton
Consists of the bones in the trunk area which includes the skull, spine (vertebral column), ribs and breastbone (chest cavity), pelvis, and tail
Bones of the skull are flat or irregular in shape and form the framework for the brain, mouth, eyes, and nasal cavities.
The vertebral column consists of a flexible column of small bones (vertebrae) that forms the basis of the skeleton
Hip bones are 2 large flat bones attached to the spine and sacrum that form the pelvis or pelvic girdle and cavity
The ribs and breastbone (sternum) along with the thoracic vertebrae form the chest cavity

9. Axial skeleton

10. Skeletal system Appendicular Skeleton
Consists of the forelegs and hind legs that are used for locomotion, grooming, and to some extent, for defense and feeding.
The forelimbs have no skeletal attachments to the axial skeleton or trunk, but are connected by muscles
The hind limbs are attached to the pelvis at the hip joint

11. Appendicular skeleton

12. Skeletal system
Articulations (joints) are the union of two or more bones or cartilages held together by ligaments, tendons, or a tough fibrous capsule.
Joints are classified by their structure and movability
Freely movable joints have a joint cavity between the two surfaces, the bones are covered with a smooth cartilage, and the bones are held by ligaments

13. articulations

14. Muscular system
Muscles are red, lean meat that compose about 50% of the equine’s total body weight that are stimulate to contract or change shape by nerve impulses from the brain and in turn send nerve impulses back to the brain indicating the degree of contraction so that movement is smooth.

15. Muscular system
There are three basic muscle types in the muscular system:
Smooth Muscles are involuntary muscles
Sometimes called visceral muscle
Found in the digestive system and in the uterus of females
Capable of prolonged activity without fatigue

16. Muscular system Cardiac Muscles are involuntary striated muscles
Found only in the heart
Contractions of the cardiac muscles require no nerve stimulus
Contractions are rhythmic and require no conscious control

17. Muscular system
Striated (Skeletal) Muscles are usually attached to bones of the skeletal system either directly or by tendons and act voluntarily
Bones serve as levers and the muscles move the body voluntarily under the direct control of the will
Skeletal muscles are usually arranged in opposite sets so that one set of muscles bend the limb (flexor muscle) and the other set straightens it (extensor muscle)
Voluntary muscles become fatigued and need rest after a short period of time

18. Muscular system
Tendons eliminate undue friction to allow muscles to act more freely
The tendon sheath is a synovial sac through which a tendon passes and which provides synovia to lubricate the surrounded tendon.
The tendon bursa does the same thing as the sheath except the tendon does not pass through it. The tendon bursa is a synovial sac interposed between the tendon and the surface over which it comes in contact which lubricates and cushions the tendon
Both are found mainly near joints