- State that homeostasis involves
maintaining the internal environment at a
constant level or between narrow limits,
including blood pH, oxygen and carbon dioxide
concentrations, blood glucose, body temperature
and water balance.
- The internal environment consists
of blood and tissue fluid. Cross reference with
|Explain that homeostasis involves
monitoring levels of variables and correcting changes in
levels by negative feedback mechanisms.
|State that the nervous and the
endocrine systems are both involved in homeostasis.
- State that the nervous system consists of the
central nervous system (CNS) and peripheral
nerves and is composed of special cells called
neurons that can carry electrical impulses
- No structural or functional
division of the nervous system or details of
impulse transmission or synapses are required.
|Describe the control of body temperature including
the transfer of heat in blood, the role of sweat glands
and skin arterioles, and shivering.
- State that the endocrine system consists of
glands which release hormones that are
transported in the blood.
- The nature and action of hormones
or direct comparisons between nerve and endocrine
systems are not required.
- Explain the control of blood glucose
concentration, including the roles of glucagon,
insulin and alpha and beta cells in the
- Alpha islet cells produce
glucagon; beta islet cells produce insulin. The
regulation of glucose concentration within normal
limits and the feedback mechanisms should be
stressed. The effects of adrenaline are not
|Outline the need for excretion in all living
|State that excretory products in plants include
oxygen, and in animals they include carbon dioxide and
- Discuss the relationship between the different
nitrogenous waste products and habitat in
mammals, birds and freshwater fish.
- Surplus amino acids must be
degraded to relatively harmless
nitrogen-containing compounds. Freshwater fish
can get rid of ammonia, although highly toxic
(due to its basicity), because it can be diluted
by the readily available water. Birds are unable
to carry too much water so they excrete uric acid
which is insoluble and expelled as a paste (most
of the water is removed before excretion).
Mammals excrete urea. Some desert mammals produce
very concentrated urine (having a long loop of
|The Human Kidney
- Outline the role of the kidney in
excretion and the maintenance of water balance.
- Draw the structure of the kidney.
- Include the cortex, medulla,
pelvis, ureter and renal blood vessels.
|Draw the structure of a glomerulus and
|Explain the process of ultrafiltration
including blood pressure, fenestrated blood capillaries
and basement membrane.
- Define osmoregulation.
- Osmoregulation -- the control of
the water balance of the blood, tissue or
cytoplasm of a living organism.
|Explain the reabsorption of glucose,
water and salts in the proximal convoluted tubule,
including the roles of microvilli, osmosis and active
- Explain the roles of the loop of Henlé, medulla,
collecting duct and ADH in maintaining the water
balance of the blood.
|Compare the composition of blood in
the renal artery and renal vein, and compare the
composition of glomerular filtrate and urine.
|Outline the structure and action of
kidney dialysis machines.