Anatomy of the Muscular System

Muscular System

• The muscular system consists of voluntary and involuntary muscles
• Voluntary muscles are under the organism's conscious control, examples include triceps
• Involuntary muscles automatically move to regulate body functions, examples include heart and diaphragm
• Muscles are composed of fibrous cells that contract and relax in pairs
• Tendons are long, thin, stretchy tissues that attach muscles to bones
• Muscles pull against bone when they contract, causing movement

Skeletal System

• The skeletal system provides structure and support to the body
• It protects internal organs and makes locomotion possible
• Bones are composed of 50% water, 26% minerals (calcium and phosphorus), 20% protein, and 4% fat
• The core of bones is soft and spongy, called marrow, which produces new red blood cells
• Cartilage is a soft, tough tissue found between bones that cushions joints
• Ligaments are long, stretchy tissues that hold joints together

Skeletal System of Animals

• The horse skeleton consists of:
  • Cervical bones (7)
  • Thoracic bones (13)
  • Lumbar bones (7)
  • Sacral bones (3)
  • Cranial bones (1)
  • Caudal bones (tail bones)
• The dog skeleton consists of:
  • Scapula (shoulder blade)
  • Pelvis (hip bone)
  • Clavicle (collar bone)
  • Femur (thigh bone)
  • Sternum (breast plate)
  • Fibula (outer lower leg bone)
  • Ulna (inner lower leg bone)
  • Tibia (shin bone)
  • Calcis (heel bone)
  • Radius (forearm bone)
  • Metacarpal bones (wrist bones)
  • Tarsal bones (ankle bones)
  • Metatarsal bones (foot bones)
  • Phalanges (toe bones)

Nervous System

• The nervous system consists of the central nervous system (brain and spinal cord) and peripheral nervous system (nerves)
• The brain coordinates all aspects of animal function
• The spinal cord is the main "highway" for nerve impulses to travel from the brain to the rest of the body
• Nerves branch out and reach the rest of the body, using electrical impulses to send messages from the brain throughout the body

Circulatory System

• The heart is a muscle that pumps blood with 4 chambers and 2 valves
• Arteries carry oxygen-rich blood from the lungs and heart to tissues
• Veins carry blood back from tissues to the lungs and heart
• Blood consists of:
  • Plasma (liquid part of blood)
  • Red blood cells (carry oxygen and carbohydrates)
  • White blood cells (fight pathogens)
  • Platelets (make blood clot)

Respiratory System

• The respiratory system brings oxygen into the body and expels carbon dioxide
• The exchange of gases happens inside the lungs in the alveoli
• The lungs expand and contract due to the movement of the diaphragm
• The respiratory system consists of:
  • Nose (external opening)
  • Pharynx (connects esophagus and trachea)
  • Larynx (voice box)
  • Trachea (wind pipe)
  • Lungs

Excretory System

• The excretory system removes waste materials from the body
• The kidneys remove waste materials from the blood
• The bladder holds liquid waste (urine)
• The ureters connect the bladder to the urethra
• The urethra empties urine to the exterior of the animal

Digestive System

• The digestive system breaks down food into usable energy
• The digestive system removes unusable food from the body
• The digestive system consists of:
  • Mouth
  • Esophagus
  • Stomach
  • Small intestine
  • Cecum
  • Large intestine
  • Rectum
  • Anus

Endocrine System

• The endocrine system is a group of ductless glands that secrete hormones to regulate certain functions of the body
• The endocrine system plays a large role in reproduction, digestion, growth, and other functions
• Examples of endocrine glands include:
  • Hypothalamus
  • Pituitary
  • Pancreas
  • Liver
  • Thyroid
  • Adrenal

Why Study Anatomy and Physiology?

• Efficient production of livestock requires understanding the anatomy and physiology related to production
• Production includes muscle gain, milk or egg production, and hair or wool production
• Raising animals requires an understanding of the needs required for animal wellbeing
• Animal wellbeing is caring for animals so that their basic needs are met and they do not suffer