Control Systems Flashcards
What does cell metabolism lead to
build-up of waste products in the blood, including carbon dioxide and urea
How is urea produced and removed
produced from the breakdown of excess amino acids in the liver and is removed by the kidneys
Describe the structure of the urinary system
a) renal artery and vein - vein = carry cleaned blood back to the body, arteries = carry blood from the body to the kidneys
b) kidneys - remove substances including urea from the blood and make urine
c) ureters - carry urine from the kidneys to the bladder
d) bladder - stores urine
e) urethra - urine flows through the urethra to the outside of the body
Describe possible treatments for kidney failure
kidney dialysis - blood is passed through a dialysis machine to remove waste urea and excess substances before the blood is returned to the body.
organ donation - a healthy kidney from another person is placed in the body and connected to the blood system, so that waste substances are removed from the blood
Describe the structure of a nephron
a) glomerulus and Bowman’s capsule - glomerulus = small knot of capillaries, bowman’s capsule = cup shape. filtration of small molecules from blood into tubule, including water, glucose,salts and urea
b) convoluted tubules -
c) loop of Henlé
d) collecting duct
Explain how the structure of the nephron is related to its function in filtering the blood and forming urine (osmoregulation),
the blood in the glomerulus is under high pressure. the walls of the glomerulus and bowman’s capsule are leaky so small molecules filter from the blood into the capsule. the large surface area of the glomerulus and capsule means filtration happens as quickly as possible. the convoluted tubule and loop of henle lie close to a capillary, so that glucose and water can be reabsorbed into the blood from the tubule
describe the role of ADH (produced by the pituitary gland) in regulating the water content of the blood
to control the amount of water reabsorbed from the nephrons. this regulates the water content of the blood
describe how ADH production is controlled by a negative feedback mechanism
an increase in blood water content causes the pituitary gland to be reabsorbed by the collecting duct in the kidneys so more water is excreted by the kidneys. a decrease in blood water content causes the pituitary gland to secrete more ADH, which causes less water to be excreted by the kidneys. this is a negative feedback mechanism because a change in blood water content causes can opposite change that restores the normal blood water content
what is the menstrual cycle controlled by
menstrual cycle is controlled by the hormones
oestrogen and progesterone
Describe the stages of the menstrual cycle
1) mensuration is the breakdown of the uterus lining. it begins on day 1 of the cycle and usually lasts between 4 and 7 days.
2) during the second week, the lining of the uterus is gradually built up
3) ovulation is the release of an egg from an ovary. this usually takes place around day 14.
4) days 14-16 are the days when fertilisation is most likely to take place
5) the lining of uterus continues to build up throughout weeks 3 and 4
6) if fertilisation occurs then the uterus lining is maintained and mensuration does not happen
Explain why the uterus lining is maintained if fertilisation occurs
the embryo that develops form a fertilised egg needs to embed in the thick uterus lining, so that it can get nutrients from the mother
Describe how oestrogen, progesterone, FSH and LH control the menstrual cycle
s
describe how the menstrual cycle is controlled by a negative feedback mechanism
changes caused by the release of of hormone inhibit the secretion of other hormones. for example, progesterone inhibits FSH and LH
Explain how the structure of an egg is adapted to its function
> cytoplasm to provide nutrients that the embryo will use to grow and develop
haploid nucleus contains one set of genetic material
cell membrane changes immediately after fertilisation to block entry of other sperm
Explain how the structure of a sperm cell is adapted to its
function
> acrosome containing enzymes to digest into the egg
haploid nucleus contains one set of genetic material
middle section containing mitochondria that release energy from respiration to power tail
tail for movement
describe the advantages and disadvantages of infertility treatments
Egg donation:
A) used when woman of the couple has no eggs in her ovaries
D) hormones used to collect eggs may cause a bad reaction. the egg donor may want access to the child.
IVF:
A) useful if a man produces only a few healthy sperm
D) babies may be born early, which can cause problems at birth or later in life
Surrogate mother:
A) used when the woman of the couple cannot grow an embryo in her uterus
D) some surrogate mothers find it hard to hand over the baby to the couple
Hormones:
A) used when the woman’s hormones are not enough to cause ovulation
D) there is a greater risk of having several babies at the same time. these babies tend to be born earlier than normal, which can cause problems at birth or later in life
how is the sex of a person is controlled
the sex of a person is controlled by one pair of
chromosomes, XX in a female and XY in a male
Describe Edward Jenner’s contribution to the development of vaccines
Edward Jenner gave a boy a pathogen that causes a mild disease called cowpox. the boy developed cowpox and recovered,. later Jenner gave the boy the pathogen that causes a dangerous disease called small pox. the boy did not develop small pox - the cowpox vaccine had made him immune to smallpox
Explain the process of immunisation
1) a vaccine containing a dead or weakened pathogens injected into the body. it has antigens on its surface.
2) a type of white blood cell, called a lymphocyte, with an antibody that perfectly fits the antigen is activated
3) this lymphocyte divides over and over again to produce clones of identical lymphocytes
4) some of the lymphocytes secrete large amounts of antibodies. the antibodies stick to the antigens and destroy the pathogen
describe the advantages and risks associated with immunisation
risks:
> some people get a mild reaction of swelling or soreness, or a mild form of the disease
> very rarely a person has a major harmful reaction
advantage:
> immunity is produced without being ill
> immunity lasts a long time, often for life
> if most people are immune, then the few unvaccinated people are also likely to catch the disease
Describe the role of memory lymphocytes in secondary
responses to antigen
memory lymphocytes are ready to respond immediately if the same antigen ever turns up again.
explain how sex linked genetic disorders are inherited
s
Describe the production of monoclonal antibodies, and the use of them
s
Describe how the exponential growth of a population of bacteria can lead to rapid development of an infection
S
