Hormonal Coordination and Endocrine System in Humans

Endocrine System

Network of glands producing hormones in the body.

hormones

a chemical substance, produced by a gland and carried in the bloodstream, which alters the activity of specific target organs

Pituitary Gland

attached to bottom of brain

master gland

produces and stimulates many hormones that regulate body conditions

Thyroid Gland

neck

produces thyroxine that regulates rate of metabolism, heart rate and temp

how does pituitary gland stimulate thyroid gland

detects low levels of thyroxine, it produces (thyroid stimulating hormone)TSH which stimulates thyroid gland to produce more thyroxine-negative feedback

Adrenal Gland

on top of kidneys

Produces hormones like adrenaline to prepare for flight or fight i.e increasing heart rate

Pancreas

infant of kidneys

produces insulin which helps regulate blood glucose levels

Testes

produces testosterone

producing sperm cells

Ovaries

produces oestrogen for menstrual cycle and puberty

producing eggs cells

how does endocrine differ from nervous system

endocrine=relies on hormones secreted by glands transported by blood

=slower but effects last longer

=act more generally

nervous=electrical impulses which travel along nerve cells

=faster but not long lasting

=precise

Kidneys

Organs that filter blood and produce urine.

what are the three substances removed from body

water

ions

urea

How is water lost from the body?

leaves body via skin during sweat and lungs from breathing out

How are ions lost from the body?

sweat and urine

How is urea lost from the body?

filtered out of blood via kidneys and out via urine

protein digestion leading to excess amino acids process

-digestion of protein from diet results in excess amino acids which need to be excreted.

-in the liver these amino acids are deaminated to form ammonia

-ammonia is toxic so is converted to urea and filtered out of blood and excreted via urine

describe how kidneys produce urine

The blood is filtered

Urea, glucose, water, ions removed from blood

Useful molecules like glucose, some ions and water are selectively reabsorbed

this is called selective reabsorption

ADH (Antidiuretic Hormone)

hormone that targets kidneys for water conservation.

ADH effect on permeability of kidney tubules

receptor detects if water content is too high or too low and a response is produced

if too high-pituitary gland releases less ADH so less water is reabsorbed via kidney tubules

if too low-pituitary gland releases more ADH so more water is reabsorbed via kidney tubules

dialysis machine

The machine used to remove urea and excess mineral ions from the blood when the kidneys fail.

adv of dialysis machine

-can be done at home

-no operation risk

-readily available

disadv of dialysis machine

-expensive as required long term

-may cause blood clots

-risk of infection

kidney transplant

replacement of a diseased kidney with one that is supplied by a compatible donor

adv of transplant

-patient can live a normal life

-cheaper

disadv of transplant

-rejection by white blood cells in body

-must take immune suppressant drugs which increase risk of infection

-shortage of donors

-operation risk

puberty

the period of sexual maturation, during which a person becomes capable of reproducing

sexual characteristics in men

facial hair

muscular body

produce sperm

sexual characteristics in women

breast develop

hips widen

menstrual cycle starts

Menstrual Cycle

Monthly cycle regulated by hormones in females.

FSH (Follicle Stimulating Hormone)

pituitary gland

causes egg to mature in ovaries

stimulates ovaries to produce oestrogen

oestrogen

ovaries

causes lining of uterus to grow

stimulates release of LH

LH (Luteinizing Hormone)

pituitary gland

stimulates release of egg at day 14 ovulation

hormonal methods of contraception

- Oral contraceptives (Pills)-contains oestrogen and progesterone but has nausea side effects

- The Patch-contains oestrogen and progesterone, short term

non hormonal methods of contraception

-barrier methods-condom to stop sperm reaching egg

stop intercourse

Fertility Treatments

Methods to assist conception, including IVF.

can give infertile couple a child

IVF steps

-stimulate the ovaries

-collecting the eggs

-fertilisation

-embryo transfer

risk to IVF

multiple births

low success rate

emotionally stressful

adrenaline

a hormone secreted by the adrenal glands, especially in conditions of stress, increasing rates of blood circulation, breathing, and carbohydrate metabolism and preparing muscles for exertion.

thyroxine

thyroxine is produced and secreted by follicle cells in the thyroid gland. it targets all cells in the body and increases overall body metabolism.

role of thyroxine and adrenaline in negative feedback

when levels are too high the secretion is inhibited.