module 3 - 8.3 blood, tissue fluid and lymph Flashcards
what is blood?
specialised transport medium that is also a connective liquid tissue
what are the functions of blood?
- transport
- defence (immune system)
- thermoregulation
- maintaining pH of bodily fluids
what are erythrocytes?
red blood cells
what are platelets?
fragments of large megakaryocytes found in bone marrow, also involved in blood clotting
what are leucocytes?
white blood cells (e.g. lymphocytes and phagocytes)
what is unusual about human red blood cells?
they have no nucleus, they are packed with mRNA and ribosomes to make proteins
what are the adaptations of human red blood cells?
flattened biconcave disc shape - large SA:V for efficient gas exchange
large amount of haemoglobin - for transporting oxygen
no nucleus or organelles - maximises space for Hb so more oxygen is transported
what does 8% of blood plasma consist of?
plasma proteins (half are a group of proteins called ALBUMINS)
what are albumins?
water soluble transport proteins that carry molecules and ions in the blood
what is the function of albumins?
regulates osmotic pressure of blood (done by proteins so is called oncotic pressure - albumins displace water molecules)
how do albumins cause dipoles?
they have a hydrophilic R group which means they can then hydrogen bond with water
the typical human blood oncotic pressure is negative, what does this create?
a tendency for water to move into the blood from surrounding tissue by osmosis
what is the blood pressure developed by the contraction of the heart?
high
what is the pressure developed by the contraction of the heart called?
hydrostatic pressure
what happens at the arteriole end of the capillary bed when hydrostatic pressure has fallen to +4.6kPa?
fluid is forced out the capillaries by the higher pressure in the blood, creates TISSUE FLUID