Higher Human Biology: Unit 2

What is fertilisation?

fusion of male and female gametes to form a zygote

What do the testes do?

Location of sperm production within the seminiferous tubules
Manufactures testosterone in the interstitial cells

What are sperm?

male gametes that are capable of movement but need fluid and energy for mobility

What is semen?

mixture of sperm and seminal fluid from seminal vesicles and prostate glands

What does the seminal vesicle do?

Produces fructose-containing liquid with hormone-like compounds that stimulate contraction in the female reproductive tract

What does the prostate gland do?

Produces enzyme-containing liquid that makes sure semen is the right viscosity for sperm mobility

What are spermatozoa?

mature sperm cells

What do interstitial cells do?

produce testosterone

What are the seminiferous tubules?

Tubes inside the testes where the sperm cells are formed

What is an ovum?

mature egg

What does the follicle do?

protects the developing ovum and secretes progesterone

What does the corpus luteum do?

secretes progesterone

What is the corpus luteum?

Structure left after ovulation

What is the oviduct?

site of fertilization

What is the uterus?

Site of implantation and development of zygote

What is the endometrium?

lining of the uterus

What structure releases FSH?

pituitary gland

What structure releases ICSH?

Pituitary gland

What structure releases testosterone

Interstitial cells

What does FSH do?

stimulates sperm production

What releases FSH?

pituitary gland

What releases ICSH?

Pituitary gland

What releases LH?

pituitary gland

What releases testosterone?

interstitial cells

What releases oestrogen?

Follicle of the ovary

What releases progesterone?

corpus luteum

What does FSH target?

seminiferous tubules

What does ICSH target?

Interstitial cells

What does testosterone target?

Pituitary gland

What does testosterone target?

Seminal vesicles

What does testosterone target?

Prostate gland

What does FSH target?

Ovaries

What does LH target?

Ovaries

What does oestrogen target?

Endometrium

What does oestrogen target?

Cervix

What does oestrogen target?

Pituitary gland

What does progesterone target?

Endometrium

What does progesterone target

Pituitary gland

What does ICSH do?

stimulates production of testosterone

What does testosterone do?

stimulates sperm production

What does testosterone do?

Stimulates prostrate gland to secrete fluids

What does testosterone do?

Inhibits pituitary gland

What does FSH do?

Stimulates follicle to mature

What does FSH do?

Stimulates oestrogen production

What does LH do?

Triggers ovulation

What does LH do?

Stimulates development of the corpus luteum

What does oestrogen do?

Causes proliferation of the endometrium

What does oestrogen do?

Thins cervical mucus

What does oestrogen do?

Triggers the release of LH

What does progesterone do?

Inhibits pituitary gland from releasing FSH and LH

What does progesterone do?

Vascularises endometrium

What is negative feedback?

High concentrations of testosterone inhibits pituitary gland from releasing FSH, LH and ICSH

What is stage 1 of the menstrual cycle?

Follicular Phase

What is stage 2 of the menstrual cycle?

Luteal Phase

How long is stage 1 of the menstrual cycle?

Day 1-14 (14 days) (2 weeks)

How long is stage 2 of the menstrual cycle?

Day 15-28 (14 days) (2 weeks)

What happens during stage 1 of the menstrual cycle?

FSH is released which releases oestrogen

What happens during stage 2 of the menstrual cycle?

Follicle develops into a corpus luteum which secretes progesterone

What happens if fertilisation occurs?

The negative feedback loop doesn't happen

What is negative feedback?

Lack of LH leads to degeneration of corpus luteum
progesterone levels drop
Pituitary is no longer inhibited

What is a hormone?

chemical messenger released by an endocrine gland

What is an endocrine gland?

Gland that produces and releases hormones

What is puberty?

Sequence of physical changes that prepare you for reproduction

Hypothalamus

Region of the brain that secretes releaser hormones that triggers puberty

Pituitary gland

Gland in the brain that releases many hormones

Negative feedback

System of maintaining a steady state in various body systems

What is contraception?

the deliberate prevention of pregnancy

What are the physical methods of contraception?

Abstinence
Barrier methods
IUD
Vasectomy
Hysterectomy

What is abstinence?

not having sex

What is an example of a barrier method?

Condom, diaphragm, cervical cup

What is a barrier method?

Blocking sperm from reaching the egg

What does an IUD do?

Alters cervical mucus and prevents implantation of fertilised egg

What is a vasectomy?

Cut and tie sperm ducts, preventing release of sperm during intercourse

Signs of a fertile period in women

Thin, watery mucus and an Increase in body temperature after ovulation

How is a women's fertility described?

Cyclical

How is a man's fertility described?

Continuous

infertility treatments

Stimulating ovulation
IVF
ICSI
Artificial Insemination

When is stimulating ovulation used?

When a woman fails to ovulate and to collect eggs for IVF

When is artificial insemination used?

When the male has a low sperm count

When is IVF used?

Blockages in oviduct

When is ICSI used?

Defective sperm

What is preimplantation genetic diagnosis?

allows detection of genetic abnormalities prior to implantation during IVF

What is stimulating ovulation?

Ingesting drugs that mimic FSH and LH, ingesting drugs that prevent the negative feedback effect of oestrogen on FSH secretion

What is artificial insemination?

the injection of semen into the vagina or uterus other than by sexual intercourse.

What is IVF?

The egg is fertilised outside the woman's body and then implanted back into her uterus.

What is ICSI?

injecting the sperm into the egg's cytoplasm

What are the chemical methods of contraception?

Oral contraceptive pills
Progesterone-only Pills/Mini pills
Morning-after pills

What does the morning after pill do?

Emergency contraceptive pill that prevents ovulation and implantation of fertilised egg

What does mini pills do?

Cause the thickening of cervical mucus, reducing the sperm's access to the uterus

What do oral contraceptives do?

Contain hormones (oestrogen and progesterone) to inhibit FSH/LH production so that no eggs mature/develop

What is preimplantation genetic diagnosis?

Identifies single gene disorders and chromosomal abnormalities

How can a female's fertile periods be described

Cyclical

How can a man's fertile periods be described?

Continuous

How can you identify a woman's fertile period?

Increase in body temperature after ovulation

How can you identify a woman's fertile period?

Production of thin, watery mucus

preimplantation genetic diagnosis

Genetic profiling of embryos before implantation during fertility treatments

What is a dating scan?

Carried out between 8 and 14 weeks and it determines preganancy stage and due date

What is an anomaly scan?

Carried out between 18 and 20 weeks and it is used to determine if there is any abnormalities in the fetus

What is amniocentesis?

Sample of foetal cells taken from amniotic fluid

Disadvantage of amniocentesis

Risk of miscarriage and infection