B7 - Control and Coordination

what is endocrine system

a series of glands which secretes hormones (small chemical molecules spread through the blood stream)

what is pituitary gland

located in brain, produces many hormones, some to body some to other glands

what is thyroid gland

in neck, produces thyroxine which regulates rate of metabolism. pituitary gland releases TSH which stimulates thyroid to produce more thyroxine (negative feedback loop)

what is adrenal gland

below abs, produces adrenaline which increases heart rate and blood pressure

what is pancreas

below and behind stomach, produces insulin which regulates blood glucose concentrations

what is testes

male reproductive, produces testosterone and sperm

what is ovaries

female reproductive, produces oestrogen and egg cells

menstrual cycle

28 days long, first five days called menstruation, day 15 called ovulation

role of oestrogen

stimulates uterus lining to grow after breakdown of lining

role of progesterone

maintains uterus lining

role of LH

stimulates eggs to release on ovulation day

role of FSH

, stimulates eggs to mature in ovaries

overall hormones in mesntrual cycle

FSH stimulates ovaries to produce oestrogen. As oestrogen levels grow, they inhibit FSH, and stimulate LH (ovulation). Progesterone inhibits LH and FSH.

how do hormonal methods of contraception work

release oestrogen and/or progesterone, if oestrogen is produced in excess it inhibits FSH meaning no egg is released. If progesterone is released in excess it stimulates thick mucus in cervix which preents sperm reaching egg

how does IVF work

women are given FSH and LH to stimulate eggs to mature and be released. These are then collected and fertilised in a laboratory. The embryos are placed in an incubator to grow, before being taken out and placed in the mothers uterus.

how can hormones help with infertility

low levels of FSH is a common cause of infertility, so FSH in the form of pills can be given, with LH (to stimulate ovulation). This usually restores fertility.

What is the role of kidneys

Filter blood and remove waste products (mainly urea - made in liver), and regulate levels of ions and water.

how do kidneys regulate water

water gained from food and drinks, and lost through sweat, respiration and urine. Hypothalamus detects low conc. Of water, and signals pituitary gland to release ADH, which tells kidneys to reabsorb more water, so less urine is produced.

how do kidneys regulate filtration

tubules absorb small molecules (everything except proteins and cells), and then nephron reabsorbs useful substances (all glucose, some water, no urea) - SELECTIVE REABSORBTION.

structure of kidneys

Blood enters through Renal Arteries, and out through Renal Veins. Millions of nephrons in kidney. Tubule carries filtered fluid, and blood vessels carry cells, protein, and reabsorbed material. During filtration, the glomerulus passes substances to the Bowmans capsule (and then into the tubule).