Equine unit3 Aos2 sac 2 - physiology

Purposes of the digestive system (6) RDUEHR

- Process food to enable supply of energy and nutrients to cell body.

1. Reception of food - ingestion of food, mouth is the entry point for food and water.

2. Digestion of food - through digestive processes, food is broken down into nutrients. Mechanical digestion: is the grinding and churning of food into smaller pieces in order to break it down. Chemical digestion; digestive tract lined with mucous membranes which secrete various chemicals aiding in digestion. Microbial digestion: variety of microbes (mainly bacteria) also known as micro flora are responsible for breaking down the fibrous parts of plant material in a horses diet.

3. Uptake of nutrients into blood stream - occurs through the million of finger like projections called villi on the surface of the intestinal wall. Absorbed into the bloodstream? for use around the body.

4. Expulsion of unabsorbed material and waste - Rectum holds droppings until they are excreted through the anus.

5. Homeostasis - Maintain body fluids at the correct ph and chemical composition. As digestive system is entry point for fluids and chemicals, this system, is essential for getting required substances to help maintain homeostasis. water, electrolytes, calcium.

6. Regulation of blood volume and pressure - Blood volume and pressure is dictated by the amount of water in the bloodstream. Digestive system directly affects the amount of water and helps maintain safe levels.

Digestive system injury/ailment - management

Gastric ulcers

Lesions or open wounds in the lining of the stomach wall, Affect the squamous area of the stomach (upper portion with thinner lining). Caused when horses do not have access to food, gastric acid will build up within the stomach, once the acid reaches the squamous area the stomach lining starts to erode.

Management - stomach acid buffering treatment to allow suitable conditions for ulcers to heal. Ensure horse receives enough roughage constantly to maintain stomach acid levels. Correctly balanced diet and low stress environment. Omeprazole.

Short/long term impacts of gastric ulcers

short - Behavioural change, discomfort, weight loss, poor condition.

long - Ongoing behavioural issues indicating pain (girthiness), struggle to maintain weight, rough dull coat, colic.

Gastric perforation - when left untreated ulcers can erode through stomach lining and cause sudden death.

Urinary system functions (4)

1. Maintenance of concentrations of blood levels – The kidneys filter the blood and then reabsorb required useful materials such as Salt, Vitamins and Glucose .

2. Maintenance of homeostasis - the nephron uses pressure gradients, passive transfer and active transfer to filter and balanced the blood.

3. Regulation of blood volume and pressure - hormones are produced based on the salt and water level in the blood, based on this the kidneys reabsorb more or less water. Osmosis is used to balanced levels of water within the blood.

4. Removal of waste - Urine is taken from the kidneys to the bladder until it is convenient to expel it from the body via the urethra.

*5. Maintains fluid balance by controlling the amount of water excreted in urine.

Urinary system ailment

Uroliths - aka kidney stones/ bladder stones. While uroliths are relatively uncommon in horses they are seen more commonly in geldings. Likely due to the difference in location and length of the urethra, made from calcium and carbonate. Cause is unknown.

Signs include: stretching out to urinate with no result, dribbling urine, colic like behaviour, altered hind limb movement.

management: surgery often required, no prevention. if untreated can lead to ruptured bladder. Chronic discomfort, affect ability to work.

Function of male reproductive system (2)

1. Gamete production - Gamete cells are the reproductive cells of the horse. Each cell contains half of the genetic material required to create a new individual. Gamete cells carried in sperm.

2. Hormone production - male repro tract produces 3 main hormones. Follicle; stimulating hormone to produce sperm. Luteinizing hormone; stimulates maturation and completion of sperm. Testosterone - triggers development/function of accessory sex gland and develops secondary sex characteristics which enables mating behaviours.

Ailment of male repro system - impacts long/short term - treatment

Cryptorchidism- Only one testicle descended outside the body cavity

impacts - reduced fertility, affected hormone production, complications with castration invasive, costly and higher risk.

treatment - A more complex surgery is required to remove retained testicle.

Need to be gelded, can turn into rig if undiagnosed and gelded incorrectly.

Function of female reproductive system (4)

1. Incubation and development of foetus - Eggs are fertilised in the fallopian tube, embryo travels to the uterus. Implanted embryos develop into a foetus and placenta, The placenta is responsible for protecting the foal and providing the foal with all nutrients required for growth and development via umbilical cord.

2. Birth of foal - 3 stages of birth stage 1; pre labour 1-4hrs, stage 2 foaling; water break to when foal is born 15-20mins, stage 3 expulsion of placenta; mare must pass placenta before birthing process is over, 1-3hrs.

3. Produce gametes - Gamete cells are the reproductive cells of the horse. Each cell contains half of the genetic material required to create a new individual. Mares produce eggs from oocytes which develop with the mare in utero.

4. Produce hormones - Hormones control the mares oestrus cycle, this cycle is responsible for maturation and release of eggs from the ovaries.

Ailment of female repro system - impact and management

Irregular/infrequent ovulation - Mare’s hormones do not cycle as they should, mare does not present with standard signs of oestrus or has long gaps between oestrus cycles.

Impact - reduced fertility, struggle to get mare pregnant. Mare can become infertile chronically.

Management - Hormone injections before breeding to trigger ovulation and after breeding to hold pregnancy. Manage stress and proper nutrition.

Functions of the skin/integumentary system (2)

1. Protective covering - Skin acts as a physical barrier to protect the internal structures from trauma, radiation, and micro-organisms that may cause infection or disease.

2. Regulation of body heat / Thermoregulation - The skin contains motor neurons, hair follicles and apocrine (sweat) glands that help to regulate the temperature of the horse. The apocrine glands excrete water and salts (sweat) to cool the horse. Moisture evaporates and takes heat with it to cool the surface of the skin. When the skin is too cold the motor neurons tell the muscles to contract to stand the hair up and conserve heat.

Skin ailment - mgmt and impact

Sarcoids - tumour on the skin, caused by the bovine papilloma virus thought to be transmitted by biting flies. Small lump within the skin or on top of skin, they then spread to be more exposed, lumpy, hairless patch.

Management - challenging to treat due as tumours grow small finger like projections into the surrounding tissue, making it hard to remove all infected tissue. Aggravation to the area of the sarcoids stimulates growth. Surgery, cryosurgery, chemotherapy or topical ointments.

Impact - Discomfort dependant on area - e.g eyes, career ending if in high movement location, recurring tumours, not often malignant however raise quality of life concerns or lead to other health problems that can be life threatening. Like blindness.

Function of endocrine system

1. Secretion of regulatory hormones - Endocrine system is responsible for creating molecules (called hormones) that are used for communication within the body. Hormones transported by cardiovascular system and effect targeted cells or organs. Hormones responsible for helping the body maintain homeostasis by sending messages to and from organs with feedback on current state of body. System made up of endocrine glands.

Ailment of endocrine system - management

Cushings syndrome (pituitary pars intermedia dysfunction)

Benign tumour of the Pituitary gland, the tumour grows part of the pituitary becomes overactive and produces too much cortisol. There is Normally a feedback system within the body that stops cortisol production when the body has enough.

Management - treated by administering drugs that affect the function of neuro transmitters within the body (pergolide). Treatment is effective in most horses but expensive. *Low sugar and low starch diet.

Impacts of Cushings

Long, curly coat with delayed/no shedding of the coat

Loss of toppling muscle resulting in pot bellied appearance

Increased susceptibility to laminitis and infections

Excessive thirst and increased appetite without weight gain

Behavioural changes - aggression or lethargic

Not fatal but can lead to other infections that may be fatal, can raise quality of life concerns.