Download Topic 1: Cell biology (15 hours)

Topic 6B: Human Physiology (18 hours)
6.6(R) Hormones, Homeostasis and Reproduction (BCC p329)
Essential idea: Hormones are used when signals need to be widely distributed.
Nature of science:
1. Developments in scientific research follow improvements in apparatus—William Harvey was hampered
in his observational research into reproduction by lack of equipment. The microscope was invented 17
years after his death. (1.8) Guidance: William Harvey failed to solve the mystery of sexual reproduction
because effective microscopes were not available when he was working, so fusion of gametes and
subsequent embryo development remained undiscovered.
Understandings:
Applications and skills:
2. A gene on the Y chromosome causes embryonic gonads
6. Application: The use in IVF of drugs to
to develop as testes and secrete testosterone.
suspend the normal secretion of
3. Testosterone causes pre-natal development of male
hormones, followed by the use of
genitalia and both sperm production and development of
artificial doses of hormones to induce
male secondary sexual characteristics during puberty.
superovulation and establish a
4. Estrogen and progesterone cause pre-natal development
pregnancy.
of female reproductive organs and female secondary
7. Application: William Harvey’s
sexual characteristics during puberty.
investigation of sexual reproduction in
5. The menstrual cycle is controlled by negative and
deer.
positive feedback mechanisms involving ovarian and
8. Skill: Annotate diagrams of the male
pituitary hormones. Guidance: The roles of FSH, LH,
and female reproductive system to show
estrogen and progesterone in the menstrual cycle are
names of structures and their functions.
expected.
11.4 Sexual Reproduction (BCC p499)
Essential idea: Sexual reproduction involves the development and fusion of haploid gametes.
Nature of science:
1. Assessing risks and benefits associated with scientific research—the risks to human male fertility were
not adequately assessed before steroids related to progesterone and estrogen were released into the
environment as a result of the use of the female contraceptive pill. (4.8)
Understandings:
Applications and skills:
2. Spermatogenesis and oogenesis both involve mitosis, cell growth, two 11. Application: The average
divisions of meiosis and differentiation.
38-week pregnancy in
3. Processes in spermatogenesis and oogenesis result in different
humans can be positioned
numbers of gametes with different amounts of cytoplasm.
on a graph showing the
4. Fertilization in animals can be internal or external.
correlation between animal
5. Fertilization involves mechanisms that prevent polyspermy.
size and the development
Guidance: Fertilization involves the acrosome reaction, fusion of the
of the young at birth for
plasma membrane of the egg and sperm and the cortical reaction.
other mammals.
6. Implantation of the blastocyst in the endometrium is essential for the
12. Skill: Annotation of
continuation of pregnancy.
diagrams of seminiferous
7. HCG stimulates the ovary to secrete progesterone during early
tubule and ovary to show
pregnancy.
the stages of
8. The placenta facilitates the exchange of materials between the mother
gametogenesis.
and fetus.
13. Skill: Annotation of
9. Estrogen and progesterone are secreted by the placenta once it has
diagrams of mature sperm
formed.
and egg to indicate
10. Birth is mediated by positive feedback involving estrogen and
functions.
oxytocin.
Topic 6B: Human Physiology (18 hours)
6.5 Neurons and synapses (BCC p319)
Essential idea: Neurons transmit the message, synapses modulate the message.
Nature of science:
1. Cooperation and collaboration between groups of scientists—biologists are contributing to research into
memory and learning. (4.3)
Understandings:
Applications and skills:
2. Neurons transmit electrical impulses. Guidance: The details of structure
11. Application: Secretion
of different types of neuron are not needed.
and reabsorption of
3. The myelination of nerve fibres allows for saltatory conduction.
acetylcholine by
4. Neurons pump sodium and potassium ions across their membranes to
neurons at synapses.
generate a resting potential.
12. Application: Blocking
5. An action potential consists of depolarization and repolarization of the
of synaptic
neuron.
transmission at
6. Nerve impulses are action potentials propagated along the axons of
cholinergic synapses in
neurons.
insects by binding of
7. Propagation of nerve impulses is the result of local currents that cause
neonicotinoid
each successive part of the axon to reach the threshold potential.
pesticides to
8. Synapses are junctions between neurons and between neurons and
acetylcholine receptors.
receptor or effector cells. Guidance: Only chemical synapses are
13. Skill: Analysis of
required, not electrical, and they can simply be referred to as synapses.
oscilloscope traces
9. When presynaptic neurons are depolarized they release a neurotransmitter
showing resting
into the synapse.
potentials and action
10. A nerve impulse is only initiated if the threshold potential is reached.
potentials.
11.2 Movements (BCC p476)
Essential idea: The roles of the musculoskeletal system are movement, support and protection.
Nature of science:
1. Developments in scientific research follow improvements in apparatus—fluorescent calcium ions have
been used to study the cyclic interactions in muscle contraction. (1.8)
Understandings:
Applications and skills:
2. Bones and exoskeletons provide anchorage for
11. Application: Antagonistic pairs of muscles in an
muscles and act as levers.
insect leg.
3. Synovial joints allow certain movements but not 12. Skill: Annotation of a diagram of the human
others.
elbow. Guidance: Elbow diagram should include
4. Movement of the body requires muscles to work
cartilage, synovial fluid, joint capsule, named
in antagonistic pairs.
bones and named antagonistic muscles.
5. Skeletal muscle fibres are multinucleate and
13. Skill: Drawing labelled diagrams of the structure
contain specialized endoplasmic reticulum.
of a sarcomere. Guidance: Drawing labelled
6. Muscle fibres contain many myofibrils.
diagrams of the structure of a sarcomere should
7. Each myofibril is made up of contractile
include Z lines, actin filaments, myosin filaments
sarcomeres.
with heads, and the resultant light and dark
8. The contraction of the skeletal muscle is
bands.
achieved by the sliding of actin and myosin
14. Skill: Analysis of electron micrographs to find
filaments.
the state of contraction of muscle fibres.
9. ATP hydrolysis and cross bridge formation are
Guidance: Measurement of the length of
necessary for the filaments to slide.
sarcomeres will require calibration of the
10. Calcium ions and the proteins tropomyosin and
eyepiece scale of the microscope.
troponin control muscle contractions.
Topic 6B: Human Physiology (18 hours)
6.6(H) Hormones, homeostasis and reproduction (BCC p329)
Essential idea: Hormones are used when signals need to be widely distributed.
Understandings:
Applications and skills:
11. Insulin and glucagon are secreted by β and α
15. Application: Causes and treatment of Type I and
cells of the pancreas respectively to control
Type II diabetes.
blood glucose concentration.
16. Application: Testing of leptin on patients with
12. Thyroxin is secreted by the thyroid gland to
clinical obesity and reasons for the failure to
regulate the metabolic rate and help control body
control the disease.
temperature.
17. Application: Causes of jet lag and use of
13. Leptin is secreted by cells in adipose tissue and
melatonin to alleviate it.
acts on the hypothalamus of the brain to inhibit
appetite.
14. Melatonin is secreted by the pineal gland to
control circadian rhythms.
11.3 The kidney and osmoregulation (BCC p485)
Essential idea: All animals excrete nitrogenous waste products and some animals also balance water and
solute concentrations.
Nature of science:
1. Curiosity about particular phenomena—investigations were carried out to determine how desert animals
prevent water loss in their wastes. (1.5)
Understandings:
Applications and skills:
2. Animals are either osmoregulators or
11. Application: Consequences of dehydration and
osmoconformers.
overhydration.
3. The Malpighian tubule system in insects and the 12. Application: Treatment of kidney failure by
kidney carry out osmoregulation and removal of
hemodialysis or kidney transplant.
nitrogenous wastes.
13. Application: Blood cells, glucose, proteins and
4. The composition of blood in the renal artery is
drugs are detected in urinary tests.
different from that in the renal vein.
14. Skill: Drawing and labelling a diagram of the
5. The ultrastructure of the glomerulus and
human kidney.
Bowman’s capsule facilitate ultrafiltration.
15. Skill: Annotation of diagrams of the nephron.
6. The proximal convoluted tubule selectively
Guidance: The diagram of the nephron should
reabsorbs useful substances by active transport.
include glomerulus, Bowman’s capsule,
7. The loop of Henle maintains hypertonic
proximal convoluted tubule, loop of Henle, distal
conditions in the medulla.
convoluted tubule; the relationship between the
8. ADH controls reabsorption of water in the
nephron and the collecting duct should be
collecting duct. Guidance: ADH will be used in
included.
preference to vasopressin.
9. The length of the loop of Henle is positively
correlated with the need for water conservation
in animals.
10. The type of nitrogenous waste in animals is
correlated with evolutionary history and habitat.