Unit 8: The endocrine system Flashcards
What is a gland?
Group of cells that produce different types of hormones
What is a hormone?
Chemical compound that produces long-term or short-term changes in other tissues, by regulating and coordinating a range of bodily functions.
What are target cells?
Specific cells with receptors for specific hormones
Describe the role of circulating (blood) and local
hormones [4]
Circulating hormone: travel around the body in the blood. Examples include adrenaline and testosterone.
Local hormone: act on neighboring cells without entering the bloodstream. Examples include glucagon and serotonin.
Explain how circulating hormone levels are
regulated [4]
Regulated by “complex feedback loops” that may be influenced by:
* signals from the nervous system, such as
adrenaline –> “emotion, such as stress, releases adrenaline until stress stops and the adrenal glands stop releasing this hormone.”
- chemical changes in the blood, such as
insulin –> “body detects high blood glucose levels, causing the pancreas to release more insulin so that glucose uptake increases. This will stabilize the body to normal glucose levels, causing the pancreas to stop insulin production.” - other hormones, such as FSH –> “targets the ovary to increase estrogen production to enhance ovulation. Once this is achieved, it triggers a loop where FSH production stops and estrogen levels decrease.”
Explain the relationship between the hypothalamus and the pituitary gland [4]
The hypothalamus and the pituitary gland are together responsible for homeostasis.
1. Hypothalamus: part of the brain that controls the pituitary gland.
a. Neurohormones: directly influence the pituitary
gland
b. Nerve impulses: from the hypothalamus also
stimulate the pituitary gland.
2. Pituitary gland: endocrine gland located in the brain below the hypothalamus. It secretes hormones that help regulate a wide range of bodily functions including growth, and water and temperature regulation.
Hormone + function of “hypothalamus” [2]
Neurohormones –> stimulate pituitary gland
Hormones + function of “pituitary gland” [7]
Anterior:
1. ACTH –> stimulate adrenal glands
2. LH - FSH –> stimulate ovaries and testes
3. TSH –> stimulate thyroid glands
4. PROLACTIN –> stimulate mammary glands to produce milk
5. GROWTH HORMONE (GH) –> stimulate soft tissues and bones to increase cell reproduction
Posterior:
1. ADH (Antidiuretic hormone) –> Controls thirst: acting on the kidneys for an increase in water reabsorption during dehydration.
2. OXYTOCIN –> Acts on the uterus during childbirth or the mammary glands to stimulate the release of milk. Positive feedback processes.
Hormone + function of “pineal gland”
Melatonin –> regulates sleep cycles through circadian rhythms
Hormone + function of “thyroid gland”
Thyroid hormone –> regulates metabolism
Hormone + function of “parathyroid gland”
Parathyroid hormone –> increase calcium absorption by bones
Hormones + function of “pancreas”
Insulin –> reduce blood glucose after eating
Glucagon –> increase blood glucose during fasting
Hormones + function of “adrenal glands”
Adrenaline (epinephrine) –> Increase: HR, Breathing Rate and glucose uptake
Hormones + function of “testes”
Testosterone –> Sperm production and muscle strength
Hormones + function of “ovaries”
Estrogen + progesterone –> Menstrual cycle and ovulation
