Blood & Nervous System

Principal parts of the system. Heart Lungs Arteries Capillaries Veins

The heart. Composed of four chambers Pumps to the lungs then around the body

The Lungs Responsible for infusing the blood with Oxygen and removing Carbon Dioxide

Arteries, Veins, Nerves All three come down the leg side by side. VAN – vein, artery, nerve. The vein is dorsal the nerve is palmar. Veins are thin walled with one way valves. Arteries are thick muscular walled vessles. Nerves thin bundles of white fibres.

Arteries Arteries carry blood from the heart and lungs to the various tissue of the body Foot contains 4 pairs of Arteries Digital Coronal Paracuneal Circumflex a. of P3.

Medial Digital A. Circumflex A. of P.1. Circumflex A. P.2 Proximal Nav. A. Coronal A. Distal Nav. A. Circumflex A. P.3 Dorsal branch Digital A. Paracuneal A.

B C F G H A D E I

Arteries of the Foot Digital Artery Coronal Artery Dorsal A. of P.3 Proximal Nav. Artery Coronal Artery Dorsal A. of P.3 Distal Nav. Artery Paracuneal Artery Cirucumflex a. of P.3

Circumflex a . Of p2. Dorsal plexus Dorsal a. or preplantar a. of p.3 Solar corium

Incorrect trimming and shoeing can have a direct impact on two arteries The circumflex artery of P.3, by causing too much pressure on the sole The Paracuneal artery of the frog , by over trimming and the incorrect application of a frog pressure devise

Veins Digital veins – drain the digital A. Coronal veins make up the venous plexus on the lateral cartilage Paracuneal veins drain the Para. A. Circumflex veins drain the circumflex A.

5 Corium Coronary corium produces majority of hoof wall Laminar corium terminal papillae – white line Solar corium – horny sole Frog corium - frog Perioplic corium - periople

Nerves The body has both Sensory and Motor nerves. Sensory nerves send messages to the brain. Motor nerves send messages from the brain to muscles Only Sensory nerves are present below the Carpus or Tarsal joints

Sensory Nerves of the Digit Palmar Digital Nerve, medial and lateral Divides about the Metacarpo – phalangeal joint to form two or more main branches.

Sensory Nerves of the Digit Lateral Palmar Nerve Dorsal Branch, Digital Nerve Middle Branch Digital Nerve Posterior Branch Digital Nerve

Nerve blocking/Denerving Nerve blocking – temporary removal of sensation with the use of local anesthetic Denerving – permanent loss of sensation by surgery

De - Nerving Commonly done either high or low. High denerving will remove most or all sensation from the fetlock down. Low denerving will remove most sensation from the heel area of the digit. Denerving makes it impossible for the body to be aware of injury or infection.

Site of denerving High Low

Self Test The vascular system of the leg is made up of different parts. What are they? Arteries can best be described as? How many Coria are there in the foot? AVA stands for what? The two most important blood vessels for a farrier to be aware of are? There are many small blood vessels that pass through the solar surface of P.3. True or False There is a major blood vessel that forms a loop within P.3. what is it? Loss of blood supply to tissue is called? There are two types of nerves what are they? Which type are found in the leg? Why? What is the difference between “nerve blocking “ and “denerving”?