Feedback loops

Question 1

How is the hypothalamus connected to the anterior pituitary

Answer 1

Blood vessels

Question 2

How does the hypothalamus work with the anterior pituitary

Answer 2

When the hypothalamus wants the anterior pituitary to produce or stop producing a hormone it releases a releasing or inhibiting factor (hormones) into the bloodstream which travels via blood vessels to the anterior pituitary

Question 3

Hormones released/produced by the anterior pituitary

Answer 3

Growth hormone, Gonadotrophins- follicle stimulating hormone and luteinizing hormone, Thyroid stimulating hormone, Adrenocorticotrophic hormone, Prolactin

Question 4

How is the hypothalamus and posterior pituitary connected

Answer 4

Nerves

Question 5

How does the hypothalamus work with the posterior pituitary

Answer 5

When the hypothalamus wants to release a hormone from the posterior pituitary it will create it itself and then pass the hormone down the neuron where it is stored in vesicles in the axon terminal, When it wants the hormone to be released it will send a nerve impulse causing exocytosis of the hormone into the blood

Question 6

Hormones secreted by the posterior pituitary

Answer 6

Anti-diuretic hormone, oxytocin

Question 7

Homeostasis

Answer 7

Maintenance of constant, carried out by the endocrine system and nervous system, maintains optimal environment

Question 8

Why is homeostasis essential and what does it ensure

Answer 8

Essential so that a constants and optimum environment is provided for cells and their enzymes, Ensures that the fluid environment of the cells has optimal amounts of water, oxygen, glucose, amino acids and ions going into the cell as well as optimal amounts of CO2, ions and urea leaving the cell

Question 9

What do feedback systems do

Answer 9

Maintain homeostasis

Question 10

Positive feedback loop

Answer 10

Giving birth- the brain recognises the baby pushing on the cervix and releases oxytocin, oxytocin then causes more contractions of the uterus meaning more pressure on the cervix resulting in the release of more oxytocin

Question 11

Stages in a feedback system

Answer 11

Stimulus- change in environment, Receptor- detects the change (E.g thermoreceptor, osmoreceptor, chemoreceptor, pain receptor), Modulator- control centre that processes the message from the receptor, Effector- carries out response, Response- opposite of the stimulus, Feedback- specific to feedback loop

Question 12

Steady-state

Answer 12

Constant changes made to compensate for changes in the environment

Question 13

Metabolism/metabolic rate

Answer 13

All chemical reactions occurring in the cells

Question 14

Catabolic reactions

Answer 14

Breaking down molecules into smaller units (E.g cellular respiration- O2 + glucose + H20 —> Energy (Mainly heat + ATP) + H20)

Question 15

Anabolic reactions

Answer 15

Building larger molecules from smaller molecules (E.g protein synthesis)

Question 16

Changing metabolic rate

Answer 16

Hypothalamus detects inadequate energy from blood passing through it and responds by secreting thyroid stimulating hormone releasing factors, The thyroid stimulating releasing factors travel via the blood to the anterior pituitary which responds by producing more thyroid stimulating hormone, Thyroid stimulating hormone travels via the blood the thyroid causing it to produce more thyroxine, Thyroxine increases the rate at which carbohydrates are broken down to release energy meaning thyroxine increases the rate at which cellular respiration occurs