Equine Anatomy

Heaves (COPD)

Chronic obstructive pulmonary disorder; caused by respiratory irritants 

• Treatment: 

  • Remove irritant

  • Increase turnout

  • Bronchodilators

Circulatory System

Supply body with nutrients and remove waste; Horses heart is quite big

• Heart

• Arteries

• Veins

• Capillaries

How does blood get back to the heart?

The walls around their foot contract and sends the blood back to the heart.

Blood Work - Circulatory Systems

• 9% of body weight (45L)

• 20% pulmonary (lung) 80% systemic

• 60% veins, 40% arteries

• Components:

  • Red blood cells

  • White blood cells

  • Platelets

  • Plasma

Blood Sampling

Jugular vein is the easy way to collect blood from the horse.

• Collected into tubes

  • Anticoagulant = plasma

  • No anticoagulant = serum

Bloodwork

• Hematocrit (PCV): percentage of RBCs in blood

  • 30-45% is normal

  • Decrease if anemic

  • Increase in stress, dehydration

• Spleen: stores and releases RBCs during exercise for increased oxygen delivery

Control Systems

• Nervous System

• Endocrine System

• Maintain homeostasis

  • Respond to external stimuli and change

Endocrine System

Glands and the hormones they produce.

The Senses

Sight

Hearing

Smell

Taste

Touch

Equine Sight

• Wide range of vision

  • Mostly monocular

  • Some binocular

• Blind spot immediately in front and behind

Tapetum Lucidum

(Reflective): night vision

Equine Eye

• Eye is flattened

  • Retina (sensitive tissue of the eye) closer to lens at bottom

  • Visual streak

• Dichromatic vision

  • See blue and yellow-green

  • Not red

• If you see the 3rd eyelid then the horse has teanus 

Tissue

Group of similar cells

Organ

group of similar tissues functioning together

System

group of organs with similar function

Organic Compounds

Carbon (C), Oxygen (O), and Hydrogen (H)

Skin and Coat

• Protecting 

• Synthesis of Vitamin D

• Temperature regulation (sweating)

• Sensation (touch)

Anhydrosis

Inability to sweat

Digestive System

• Breaks down and absorbs nutrients from food

• Discussed in greater detail in nutrition section

Urinary System

• Removes waste from the blood

• Expels wastes as urine

• Regulates pH

Respiratory System

• Exchange oxygen and carbon dioxide

• External Respiration: breathing

• Internal Respiration: oxygen used by cells

Roaring

“Roaring” caused by Laryngeal Hemiplegia

• Can block air ways - whizzling sound

• Can get surgery to improve this condition

Breathing

• Controlled by the respiratory center (medulla oblongata)

  • Also - Voluntary control

    • Phonation, parturition, defecation

  • Locomotion-respiratory coupling during gallop

    • Horses only inhales in suspension phase

EIPH (Exercise Induces Pulmonary Hemorrhage)

• Seen in performance animals:

  • Intense exercise

  • Increased pressure in pulmonary capillaries

  • Capillary walls rupture

  • Blood leaks into alveolar sac

  • Exits via nostrils (epistaxis)