Blood & Blood Vessles Flashcards
What are the three types of blood vessels?
Arteries: vessels that carry blood away from the heart
Veins: carry blood towards the heart
Capillaries: link arteries & veins. Enables diffusion of gases and solutes
Describe arteries and their function
Thick walled vessels that carry blood away from the heart.
They expand and recoil as blood pulses
Describe arterioles and their function
Small arteries that deliver blood to capillary bed
They regulate blood flow to organs & constrict in emergencies to reduce blood flow to less essential areas (vasoconstriction)
What are veins and their function?
Vessels that carry blood towards the heart.
They have semlunar valves which prevent back flow.
What are capillaries and their function?
They are microscopic blood vessels.
They link arteries and veins.
They exchange nutrients and gases and waste from blood.
What is blood?
A complex connective tissue which living blood cells are suspended in a fluid called plasma
It circulate around the body and delivers oxygen and nutrients to the organs in the body
What does blood transport around the body?
- oxygen
- nutrients
- hormones
- waste
- heat
- antibodies
What are the functions of blood?
- transportation: oxygen, nutrients, hormones
- protection: clots in response to injury, proteins against diseases
- regulation: ph in body fluids, temperature, osmoregulation.
What are the main components of blood.
- 55% blood plasma
- 45% red blood cells
- 1% white blood cells and platelets
Where are our blood cells made?
In our red bone marrow
Red blood cells
- formed by erythopesis
- made in red bone marrow
- contain a special protein called hemoglobin,
- carry oxygen from the lungs to the rest of the body and then returns carbon dioxide from the body to the lungs so it can be exhaled
Plasma in the blood
Liquid which contains 91.5% water
7% plasma protein
1.5% of other solutes ( electrolytes, nutrients )
transport blood cells throughout your body along with nutrients, waste products, antibodies
White blood cells and their function?
Also knows as leukocytes
A type of blood cell that is made in the bone marrow
White blood cells are part of the body’s immune system.
What are the two types of white blood cells
Granulocytes: contains granules ( nitro Phil s, basophils)
Agranulocytes
Contains lymphocytes and monocytes
What is hematopiesis?
The formation of blood cells that occurs in bone marrow.
Blood cells are made from a common stem cell called haemocytoblast.
Haemocytoblast differentiation
- lymphoid stem cell produces lymphocytes
- myeloid stem cells produced all other formed elements
What is haeostasis
Sequence response to stop bleeding when blood vessels are damaged.
What are the three stages of haeostasis?
- vasospasm: when the damaged muscle contracts, platelets release a chemical which enhances vaspospasm to reduce blood loss.
- platelet plug formation: platelets stick to damaged vessel to form a mass ( platelet plug)
- blood clotting: formation of fibrin threads to trap the blood.
Prothrmobinase converts prothrombin into thrombin which converts fibrogen to fibrin
What is the average blood volume in adults?
4 - 6 litres
What is the range of normal ph in the blood
7.35- 7.45
What does the term haematocrit refer too?
The percentage of cells in the blood
What shape are red blood cells
Biconcave disk
Name two substances which are transported in plasma
CO2
Waste products from tissue ( urea, hormones, nutrience )
What are plasma proteins?
They are proteins that carry out specific functions
Such as: clotting
Name two clotting factors
Prothrombin and fibrinogen
Name the two main blood groups
ABO & Rhesus
What is a phagocyte?
A white blood cell that can engulf and ingest pathogens
What are platelets?
Pieces of cells that are involved in haemostasis
What gives red blood cells their oxygen carrying capacity?
Haemoglobin
