Components of blood

what type of tissue is blood

a specialised liquid connective tissue

why is blood classified as connective tissue

it develops from mesenchyme and contains specialised cells suspended in an extracellular matrix

what are the three components of the cardiovascular system

heart, blood vessels, blood

what are the three principal functions of blood

transport, regulation, protection

what does blood transport

oxygen, carbon dioxide, nutrients, waste products, hormones, heat

give two examples of substances transported by blood

oxygen from the lungs to body cells; urea from body cells to the kidneys

how does blood transport oxygen

it carries oxygen from the lungs to body cells, mainly using haemoglobin in red blood cells

how does blood transport carbon dioxide

it carries carbon dioxide from body cells to the lungs for removal

how are nutrients transported by blood

from the gastrointestinal tract to body cells, particularly via the liver

how are waste products transported by blood

from cells to excretory organs, e.g. urea to the kidneys

how are hormones transported by blood

from endocrine glands to their target cells

what are the two regulatory functions of blood

maintaining blood pH and regulating body temp

how does blood regulate pH

blood contains buffer systems that maintain pH within the normal range

what is the normal blood pH range

7.35 - 7.45

why is maintaining blood pH important

many chemical reactions, especially protein-related reactions, depend on pH

what blood pH levels can be fatal

below 6.8 and above 7.8

how does blood help regulate body temp in cold conditions

vasoconstriction - arterioles supplying the skin narrow, less blood flows to skin surface, less heat is lost through radiation

how does blood help regulate body temp in hot conditions

vasodilation occurs - arterioles supplying the skin widen, more blood flows to skin surface, more heat is lost through radiation

which part of the brain detects changes in core temperature

the hypothalamus

what is the protective function of blood

it helps inactivate microorganisms & toxins and prevents blood loss

give examples of blood’s immune protection

antibody formation, white blood cell phagocytosis, complement system, interferons

which cells produce antibodies

B lymphocytes develop into plasma cells, which produce antibodies

two important properties of antibodies

specificity and immunological memory

what is the complement system

a series of plasma proteins circulating in the blood in an inactive state that set off a rapid self-amplifying enzymatic chain reaction called a complement cascade when triggeredwhat r

what are two functions of complement

cell lysis and opsonisation

what are interferons

proteins released by cells in response to viral infection that help activate antiviral defences

what is the main function of interferons

to interfere with viral reproduction and help prevent viruses spreading

what is haemostasis

the process that prevents blood loss following injury

why is haemostasis important

prevents fluid loss and helps prevent foreign material entering the body following injury

what are the two basic components of blood

plasma and formed elements

what is plasma

the straw-yellow liquid component of blood containing dissolved substances

what are the formed elements of blood

red blood cells (erythrocytes), white blood cells (leucocytes) and platelets (thrombocytes)

what substances are transported dissolved in plasma

nutrients such as glucose, amino acids, fatty acids

which waste products does plasma carry

carbon dioxide, urea, lactic acid

where are most plasma proteins synthesised

in the liver

what is the most abundant plasma protein

albumin

what are the functions of albumin

maintains osmotic pressure, carries hormones, carries fatty acids

what are immunoglobulins

antibodies produced by B cells and plasma cells

what are blood coagulation factors

plasma proteins involved in blood clotting

how does plasma differ from serum

serum is plasma without clotting factors

how is plasma obtained from a blood sample

1. prevent blood from clotting

2. centrifuge the sample

3. formed elements separate from the clear fluid

4. the clear fluid is plasma

how is serum obtained from a blood sample

1. allow the blood to clot

2. a blood clot forms

3. separate the clot from the clear fluid

4. the clear fluid is serum

why are red blood cells red

because they contain haemoglobin

what is the main function of red blood cells

transport most oxygen and some carbon dioxide

what proportion of formed elements are red blood cells

99%

what are the two main categories of white blood cells

granulocytes and agranulocytes

name the three granulocyte subtypes

neutrophils, eosinophils, basophils

main function & proportion of neutrophils

phagocytosis; they make up around 60-70% of WBCs

function and proportion of eosinophils

phagocytosis; approximately 2-4% of WBCs

function and proportion of basophils

involved in inflammatory responses; approximately 0.5-1% of WBCs

name the two agranulocyte subtypes

lymphocytes and monocytes

function and proportion of lymphocytes

immune responses; approximately 20-25% of WBCs

function and proportion of monocytes

phagocytosis; approximately 3-8% of WBCs

what do monocytes develop into

macrophages

where are white blood cells noramlly found

in the bloodstream and body tissues

are platelets complete cells

no - they are cell fragments without a nucleus

which cells produce platelets

produced by fragmentation of megakaryocytes

main function of platelets

haemostasis