Multiple choice Flashcards
The hormone in humans responsible for the contraction of the
uterus during childbirth
oxytocin
The structure into which the ovule develops after fertilisation
seed
The lower neck of the uterus that opens into the vagina
cervix
The cells that secrete a male sex hormone
Interstitial cells/Cells of Leydig
State any ONE function of luteinising hormone (LH)
Causes the follicle to burst open/stimulates ovulation
Stimulates the formation of the corpus luteum
Haemophilia is a blood clotting disorder. Explain why mainly males
suffer from this disorder.
It is a sex-linked disease caused by a recessive allele
carried on the X chromosome .
Males need only one recessive allele to have the disease because they have XY combination,while females have to have both recessive alleles to have haemophilia
because they have an XX combination
Suggest FOUR reasons why more teenagers nowadays have unplanned
pregnancies.
- Although contraceptives are easily available nowadays, many teenagers are not well informed about them
- Families, nowadays, are less likely to provide teenagers with care and discipline
- Teenagers are more exposed to sex in the media in these days
- Teenagers are increasingly able to make their own decisions
- Abortions are now legal and easily available
Explain why the cows and bulls with genotype RW have roan fur
and not only red or only white fur.
both alleles for fur colour are dominant therefore the are equally dominant or and both are expressed in the phenotype
Explain SIX advantages of using genetically modified organisms as a source
of food.
Control pests with specific genes inserted into the crop which is less
harmful to the environment than pesticides/ Reduce the need for the
use of chemicals
- Selecting the best genes to produce better resistant crops/stronger offspring to withstand harsh environmental conditions
- Using specific genes to increase crop yields/life stock improvement for food security
- Selecting genes to increase shelf life of plant products so that there is minimal waste
- Selecting genes that delay ripening of fruits to meet the demand locally and internationally
- Using specific genes to improve nutritional value of food for better health
- Using specific genes to introduce new traits in crops to suit specific needs of a population (e.g. to increase vitamin A in food)
another name for middle ear infection
ottis media
membrane below the scala vestibuli
reissners membrane
another name for yellow spot
fovea centralis and macula lutea
reaction of the pupil in response to stimulation of the retina by light
pupillary reflex
another name for short-sightedness
myopia
another name for long-sightedness
hypermetropia
curve of the lens of or cornea not uniform, so vertical and horizontal lines are not seen equally clearly.
astigmatism
2 main functions of nervous system
gathers information using senses
formulates responses to stimuli
function of cerebrum
- voluntary actions
- receives and interprets all sensations(sight,hearing)
- memory
function of hypothalamus
- control of body tempreture
- blood pressue
- sleep
function of cerebellum
- co-ordination of voluntary actions
- walking
- balance
- posture
function of medulla oblongata
- maintaining involuntary reflex functions
- breathing
- heart beat
what are the 3 meninges that protect the braina and the spinal cord
- dura matar
- arachnoid
- pia matar
functions of cerebrospinal fluid found between pia matar and arachniod
- cushions brain against shock
- maintains even pressure in and around the brain and spinal cord
- keeps nervous tissue moist
what makes the area of the brain much larger?
-gyri and sulci of cerebrum
what is the left and right hemisphere of the brain connected by
-corpus callosum
what are the 4 lopes of the cerebrum
- frontal lobe
- parietal lobe
- occipital lobe
- temporal lobe
what connects the 2 hemispheres of the cerbellum
vermis
function of somatic nervous system
- SNS recieves info from receptors and conveys the info to the CNS.
- transmits the impulses from the CNS to effector organs
function of automatic nervous system
controls:
- heart rate
- breathing
- digestion
- gland functions
function of nerves
nerves respond to stimuli and transmit impulses from one body organ to another.
function of nerve tissue
-sense stimuli in both the internal and external environment
- analyse and give appropriate response in various organs
-
function of schwann cells found along axon
-regenerate damaged neuron
function of myelin sheath
-the sheath insulates the axon so that it transmits impulses faster
Explain the significance of the elastic nature of the lens.
It allows the lens to change its shape/ become more convex as objects move closer
this allows the light rays to bend/refract more
so that a clear image is formed on the retina
Exocrine glands
have ducts to carry secretions to places such as the surface of the target organ
Endoccrine glands
secrete hormones into blood vessels that then transport them to target organs
what is the main difference between the endocrine system and the nervous system
the NS functions using electric nerve signals to regulate processes and the functioning of the human body while the ES using chemical signals
what are hormones
hormones are organic chemical messengers which are mostly protein.hormones act on target organs to regulate them and cause responses.
functions of hormones
- control growth and development of the body
- maintain homeostasis
- regulate metabolism and energy release
- control the process of reproduction
function of ADH
-regulates water content in blood as well as the bodys tempreture
Menstrual cycle
the cycle of changes taking place in the uterus to provide a favourable environment for the development of a foetus
A condition caused by a spinal cord injury above the first thoracic vertebra
quadriplegia
Explain why neurons are not in direct physical contact with one another
- to keep impulses moving in one direction
- to filter out unnecessary impulses
