Blood Physiology Flashcards
 how much blood does the average dog have in its body?
1.8 litres
How much blood does the average cat have within its body? 
300 mls
How many litres of blood does the average horse have with its body?
50 litres
Up to what percentage of blood can a healthy animal donate?
20%
What type of blood do arteries transport around the body?
Oxygenated
Why do arteries have thick vessel walls?
Arteries are designed to withstand the high pressure of blood from the heart
Why do arteries have smooth muscle walls?
The smooth muscle controls the diameterof the artery and regulates the flow of blood to different organs
Why do arteries not require valves to control blood flow?
Due to the presence of elastic tissue and muscle
What is the correct name for the smallest arteries?
Arterioles
What type of blood do veins transport around the body?
Deoxygenated blood
What is the common use of veins in a veterinary practice?
Collecting blood samples
What is a result of veins having thinner walls?
Veins collapse in on themselves rather than holding their shape
 Why do veins have valves?
To prevent the backflow of blood
What are the smallest veins called?
VenuIes
What are capillaries?
Small, thin-walled, permeable vessels
What are the walls of the capillaries made out of?
A single layer of endothelial cells
What is blood?
The life-maintaining fluid that circulates the body
What two parts make up blood?
- Fluid part
- Cellular part
What makes up the fluid part of blood?
Plasma
What makes up the cellular part of blood?
Blood cells
What percent of plasma is water?
90%
What components make up plasma?
- Water
- Plasma proteins
What do plasma proteins do?
Help maintain the osmotic pressure of the blood
Name four different plasma proteins?
- Albumin
- Fibrinogen
- Prothrombin
- Immunoglobulins
Where is albumin produced?
In the liver
What does albumin do?
Helps to maintain the osmotic concentration of the blood
Where is fibrinogen and prothrombin produced?
In the liver
What is fibrinogen and prothrombin involved in?
Involved in the clotting mechanism
What are immunoglobulins?
Antibodies produced by the immune system
What other substances does plasma transport?
- Electrolytes
- Gases
- Nutrients
- Waste products
- Hormones
What electrolytes are transported through plasma?
-Sodium
- Potassium
- Calcium
- Magnesium
- Chloride 
- Bicarbonate ions
What gases are transported through plasma?
- Oxygen
- Carbon dioxide
What nutrients are transported through plasma?
- Amino acids
- Fatty acids
- Glucose
What waste products are transported through plasma?
- Urea
- Creatinine
What is serum?
Plasma with the clotting factors fibrinogen and prothrombin removed
What is the technical name for white blood cells?
Leucocytes
What is the technical name for platelets?
Thrombocytes
What is the technical name for red blood cells?
Erythrocytes 
What is hemopoiesis?
The process by which all blood cells are produced from the bone marrow
Where is bone marrow produced?
- Long bones
- Pelvis
- Sternum
- Skull 
What is erythropoiesis?
Process where are red blood cells are produced in the bone marrow
What is the role of erythropoietin?
To stimulate the production of red blood cells
Where is erythropoietin produced?
The kidney
What happens as a red blood cell develops?
- The nucleus condenses and is present until the red blood cell becomes a reticulocyte
- Then becomes fine threads known as Howell-Joly bodies
- Eventually the nucleus disappears and the mature erythrocyte is released into circulation
What is the most predominant type of blood cell?
Erythrocytes 
Why are red blood cells red?
They contain haemoglobin which is required to carry oxygen
What is haemoglobin?
A complex protein containing iron
How long do erythrocytes survive in circulation?
Approximately 120 days
What is the role of the spleen in circulation?
Removes damaged or dead cells from circulation
What are leucocytes involved in?
- Immune response
- Fighting infection
- Producing antibodies
What are the two types of leucocytes?
- Granulocytes
- Agranulocytes
What are the three different types of granulocytes?
- Neutrophils
- Basophils
- Eosinophils 
What are the two different types of agranulocytes?
- Lymphocytes
- Monocytes
What percentage of white blood cells are neutrophils?
70%
What percent of white blood cells are basophils?
1%
What are two types of lymphocytes?
- B lymphocytes
- T lymphocytes
What is the largest type of white blood cell?
Monosites
What are platelets?
Cell fragments formed in the bone marrow
Where do platelets originate from?
Originate from a giant cell known as a megakaryocyte in the bone marrow
What is the lifespan of platelets?
Approximately 10 days
What are platelets involved in?
The clotting mechanism
Why are blood clots important?
To prevent excessive blood loss
What is heparin and what does it do?
- The bodies own natural anticoagulant
- Prevents unwanted clots forming in the blood vessels
What is the normal clotting time?
3-5 minutes
What vitamin is required to produce clotting factors and prothrombin?
Vitamin K
Explain the clotting mechanism
-Platelets stick to each other and to the damaged vessel to form a seal
-Platelets release thromboplastin
-Thromboplastin and calcium ions convert prothrombin into thrombin
-Thrombin convert fibrinogen into fibrin
-Fibrin fibres form a network across the damaged area that traps blood cells and forms a clot
-This seal is the vessel with a scab

What does the heart do?
Pumps blood around the body and blood vessels
Where is the heart located?
In the mediastinum of the thoracic cavity
What is the heart enclosed within?
The pericardium sac
What are the three layers to the wall of the heart?
- Endocardium (Innermost)
- Myocardium
- Epicardium (Outermost)
What is the main artery of the heart?
The aorta
What do the coronary arteries do?
Deliver oxygenated blood to the tissues of the heart
What is systole?
The contraction of the atria and ventricles
What is diastole?
The relaxation of the atria and ventricles
What is the correct term for the hearts ability to contract rhythmically and automatically without nervous input?
Inherent contractibility
Why is it important nerve impulses from the autonomic nervous system can override the inherent contractibility rate?
The heart must be able to alter its rate rapidly in order to satisfy the changing requirements of the body
What is the conduction system?
The mechanism responsible for initiating and coordinating the heartbeat
What is blood pressure?
A measurement of the force that pushes blood through the arterial circulation
What is blood pressure influenced by?
- The heartbeat
- Blood volume
- Elasticity of the blood vessel walls
When is blood pressure at its highest?
During systole 
When is blood pressure at its lowest?
During diastole
How is blood pressure measured within the body?
Via baroreceptors in the aorta/carotid arteries
What happens if blood pressure is too high in the body?
Baroreceptors tells the heart via the autonomic nerves to reduce rate and contractibility
What happens if blood pressure is too low in the body?
Baroreceptors tells the heart via the autonomic nerves to increase rate and contractibility
What is renin?
A hormone produced by the kidney in response to low blood pressure
What does renin do?
Promotes the release of aldosterone by the adrenal glands
What does aldosterone do?
Increases water absorption from the kidney nephrons meaning less water is lost in the urine
What does ADH stand for?
Antidiuretic hormone
Where is ADH released from?
The pituitary gland
Why is ADH released?
Released in response to low blood pressure and increased osmotic pressure of the blood
What are the two blood supplies for the liver?
- Hepatic artery
- Hepatic portal vein
What is the purpose of the hepatic portal system?
Enables products of digestion to be metabolise straight away
What structure carries out the roles of the lungs kidneys and digestive tract during gestation?
The placenta
What two vessels transport blood to and from the placenta?
- Umbilical arteries
- Umbilical veins
What do umbilical artery do?
Carry deoxygenated blood containing waste products from the foetus back to the placenta and to the circulation of the mother
What does the umbilical vein do?
Carries oxygenated and nutrient laden blood from the placenta to the foetus
What system is the lymphatic system are part of?
The circulatory system
What does the lymphatic system do?
Returns excess tissue fluid that athletes are capillaries back to the blood
