7 - Significant Defects Of Homeostasis

Front 1

Homeostasis definition

Back 1

The property of a system that regulates its internal environment and tends to maintain a stable, constant condition

Front 2

List some defects of homeostasis

Back 2

Oxygen deficiency

Fluid loss

Blood glucose alterations

Electrolyte and acid-base imbalances

Accumulations of waste products

Alterations in temperature

Front 3

Why is oxygen important? what is its ultimate role?

Back 3

Required for oxidative phosphorylation and production of ATP (ENERGY!)

We need energy to survive, dur

Front 4

Only need _______% depletion of ATP to cause widespread cellular effects

Back 4

5-10

Front 5

Define oxygen deficiency and name two states

Back 5

Decreased delivery of oxygen to cells or tissues

Partial = Hypoxia

Complete = Anoxia

Front 6

Mechanisms of oxygen deficiency

Back 6

-Inadequate oxygenation of blood

-Loss or reduction of blood supply (ischemia)

-Reduced transport of oxygen in blood

-Interference with oxygen utilization by the cell

Front 7

Organs most sensitive to oxygen deficiency

Back 7

Brain

Heart

Liver

Kidney

Front 8

Ex of disease/occurence leading to oxygen deficiency

Back 8

Diffuse pulmonary disease

Ischemia

Asphyxia during birth in foals (dummy foals)

Anemia

Cyanide poisoning

Front 9

Cyanide poisoning

Back 9

Interferes with oxygen utilization by cell

Death rapid inhibition of cytochrome oxidase in the mitochondria of brain neurons

Front 10

4 mechanisms that cause oxygen deficiency

Back 10

1. Lack of oxygen intake (Lungs)

2. Ischemic change causing decreased perfusion

3. Decreased carrying capacity of oxygen

4. Interference with cells to use oxygen

Front 11

Fluid loss can occur from which spaces?

Back 11

Intracellular

Interstitial

Intravascular

Front 12

What clinical signs do you expect with loss of fluid from intravascular space?

Back 12

Hemorrhage

Shock (tachycardia, low BP, increased RR)

Front 13

What clinical signs do you expect with loss of fluid from interstitial and intracellular space?

Back 13

Vomiting and/or diarrhea

Dehydration, lethargy, weakness

Front 14

Alteration in glucose: 2 states

Back 14

Hypoglycemia (low blood glucose levels)

Hyperglycemia (high blood glucose levels)

Front 15

Why is it important to have fine control of blood glucose concentration? (normal range: 3.4-5.7 mmol/L)

Back 15

Glucose affects energy production and utilization

Front 16

Which organs can ONLY use glucose to meet their energy requirements?

Back 16

**Brain

Retina

Germinal epithelium of gonads

Front 17

Clinical signs of hypoglycemia

Back 17

Seizures

Weakness/collapse

Muscle fasciculations

Depression

Ataxia

Front 18

Hypoglycemia: clinical diseases

Back 18

Insulinoma

Hepatic insufficiency/failure

Sepsis

Bovine Ketosis/Ovine Pregnancy Toxemia

Xylitol toxicosis

Front 19

What is insulinoma? what happens?

Back 19

(Dogs, cats, ferrets)

Functional beta-cell tumours of pancreas that secrete insulin

Hyperinsulinism leads to increased glucose utilization by hepatocytes, myocytes, adiposcytes and decreased glucose production by hepatocytes

Front 20

Hepatic insufficiency/failure: what happens

Back 20

Too few functional hepatocytes to maintain normal fasting blood glucose concentration

Front 21

Sepsis: what happens?

Back 21

Systemic response to bacterial infection likely due to decreased hepatic gluconeogenesis and increased glucose utilization by tissues

Front 22

What happens with bovine ketosis/ovine pregnancy toxemia?

Back 22

Increased glucose demands associated with lactation/pregnancy that are not adequately supplied

*Negative energy balance

Front 23

What happens with Xylitol toxicosis?

Back 23

(dogs, cattle and goats)

Xylitol is a potent stimulant for insulin release and leads to increased glucose uptake and utilization by cells

Front 24

Hyperglycemia can lead to?

Back 24

Cellular dehydration through loss of glucose in urine and subsequent osmotic diuresis that depletes fluids and electrolytes

Front 25

Long term hyperglycemia can potentially lead to?

Back 25

Tissue and vascular injury

Front 26

Organ systems affected by hyperglycemia?

Back 26

Endocrine/metabolic system

Renal/urologic

CNS

Opthalmic

Front 27

Most common cause for mild to moderate increases in blood glucose concentration?
Why does this happen?

Back 27

STRESS!!!!!!!

Corticosteroids cause increased gluconeogenesis and subsequent increased release of glucose from hepatocytes

They also inhibit glucose uptake by tissue cells

Front 28

Clinical diseases leading to hyperglycemia

Back 28

Diabetes mellitus (absolute or relative insulin deficiency)

Hyperadrenocorticism (Cushing's disease)

Front 29

Diabetes mellitus (DM) in dogs

-type

-what happens

-what causes it

Back 29

-Type 1 DM - insulin dependent

-Beta cell destruction leads to absolute insulin deficiency

-Often immune-mediated

Front 30

Diabetes Mellitus (DM) in cats

-type

-what happens

-associated with

Back 30

-Type 1 or Type 2 (non-insulin dependent DM)

-Type 2: insulin resistance leading to defects in insulin secretion or defects in receptors on target cells

-Can be associated with obesity in cats

Front 31

Hyperadrenocorticism:

-which species?

-What happens?

Back 31

-Dogs and horses

-Long term increase in endogenous corticosteroids leads to insulin resistance

Front 32

Mechanisms of abnormal electrolyte concentrations in blood

Back 32

1. Decreased or increased intake

2. Shifts to and from ICF

3. Increased retention via kidneys

4. Increased loss via kidneys, GIT, skin, airways

5. Disease conditions that alter electrolyte concentrations (can result in acid-base abnormalities)

Front 33

Sodium:

-Central role

-Where most important

-Main source

-Regulated by

Back 33

-Water and osmotic regulation

-Osmotically effective solute in ECF

-Dietary

-By kidneys via Ang II and aldosterone

Front 34

Types of sodium imbalance

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Hypernatremia

Hyponatremia

Front 35

Hypernatremia: Relative sodium gain reasons

Back 35

1. Inadequate water intake

2. Panting, hyperventilation, fever (insensible losses)

3. Diabetes insipidus

Front 36

Diabetes insipidus effects

Back 36

Decreased water resorption by kidneys due to lack of ADH or an inability of the kidneys to respond to ADH

Front 37

Absolute sodium gain causes

Back 37

Iatrogenic: Na containing IV fluids

Increased sodium intake without concurrent adequate water intake (salt water ingestion, play dough ingestion)

Front 38

Causes of hyponatremia

Back 38

Decreased dietary intake

Excessive loss

Front 39

Decreased dietary intake: hyponatremia

Back 39

Seen mostly in ruminants

Front 40

**Know

Excessive Loss (with continued water intake)

Back 40

1. GI loss - vomiting, diarrhea, sequestration

2. Renal loss - Addison's, prolonged diuresis

3. Cutaneous loss - sweating

4. Third Space loss - pleural or peritoneal effusion

Front 41

Potassium:

-main source

-where mostly found

-regulated by

Back 41

- Dietary

-ICF

-Aldosterone; promotes renal K+ excretion

Front 42

Potassium imbalance

Back 42

Hyperkalemia

Hypokalemia

Front 43

Causes of hyperkalemia

Back 43

Increased total body potassium

Shifting of potassium from ICF to ECF with no change in total body K

Front 44

**Know

Increased total body potassium due to

Back 44

1. Decreased renal excretion

-Renal failure

-Urinary tract obstruction

-Addison's disease

2. Iatrogenic: K rich IV

Front 45

Causes of shifting of potassium from ICF to ECF

Back 45

1. Metabolic acidosis (ex. accumulation of inorganic acids)

2. Cell lysis (ex. rhabdomylolysis)

Front 46

Causes of Hypokalemia

Back 46

Decreased total body

Shifting from ECF to ICF

Front 47

Causes of decreased total body potassium

Back 47

Decreased intake: anorexia

Increased renal excretion (osmotic diuresis, drugs)

Increased GI loss

Increased cutaneous loss

Front 48

3 fractions of Calcium in the body

Back 48

50% free calcium

40% protein bound (albumin)

10% non-protein bound (citrates & phosphates)

Front 49

Net effect of PTH on calcium levels

Back 49

Increased serum Ca via Ca mobilization (bone, intestine, kidneys)

Decreased serum P (P excretion at kidneys)

Front 50

Net effect of Vitamin D on Calcium levels

Back 50

Promotes hypercalcemia

Front 51

Hypercalcemia: increased mobilization or absorption due to?

Back 51

1. Primary hyperparathyroidism (^ PTH)

2. Hypercalcemia of malignancy (^ PTH-rp)

3. Hypervitaminosis D

Front 52

Hypercalcemia: decreased urinary excretion due to?

Back 52

Renal failure in horses

Front 53

Causes of hypocalcemia

Back 53

**1. Hypoproteinemia (hypoalbuminemia)

2. Inadequate immobilization or absorption

3. Excess renal excretion

Front 54

Examples of inadequate immobilization or absorption

Back 54

Pregnancy, parturient or lactationsal hypocalcemia

Chronic renal disease

Front 55

Examples of excess renal Ca excretion

Back 55

Ethylene glycol toxicity (antifreeze)

Front 56

What makes up increased plasma metabolites (waste products)

Back 56

Urea

Creatinine

Front 57

An increase in blood non-protein nitrogenous compounds (urea and creatinine) is called?

Back 57

AZOTEMIA

Front 58

**Causes of azotemia

Back 58

Pre-renal

Renal

Post-renal

Front 59

Azotemia always needs to be interpreted in conjunction with?

Back 59

Patients USG!!

Front 60

Pre-renal azotemia signs

Back 60

USG > 1.030

*Concentrated urine

*Any process that decreases renal blood flow (hypovolemia due to dehydration, shock)

Front 61

Renal azotemia signs

Back 61

USG: 1.008 - 1.012

*Any renal disease causing major GFR decrease

*ex. Renal failure

Front 62

Post-renal azotemia signs

Back 62

USG variable

*Any disease/disorder to distal to the nephron that interferes with urea and creatinine excretion

*Ex. urinary tract obstruction, uroabdomen

Front 63

Increased body temperature causes

Back 63

1. Pyrogenic hyperthermia or Fever/Pyrexia

2. Non-pyrogenic hyperthermia

Front 64

Pyrogenic hyperthermia

Back 64

Higher tha normal body temperature due to a changed thermoregulatory set-point in hypothalamus

**Controlled hyperthermia

Front 65

Non-pyrogenic hyperthermia

Back 65

Increased temperature due to failure thermoregulation

**Uncontrolled hyperthermia