Download NOTES- Endocrine System (feedback)

NOTES­ Endocrine System
Endocrine System
Roles of the Endocrine System
• glands that produce chemicals (hormones) released into the blood
• General role:
> Maintain homeostasis
> Regulate growth and development
> Coordinate energy use
Regulate response to stim
1
NOTES­ Endocrine System
Types of Hormones
• 1. Amines: Examples: epineprine and thyroid hormones
• 2. Prostaglandins: act as chemical messengers, but do not move to other sites
• 3. Steroid hormones: Examples: testosterone and estrogen
• 4. Peptide and Protein hormones: are the largest and most complex hormones. Example: insulin.
Glands and Hormones
2
NOTES­ Endocrine System
Hormones
• found in plants as well
• In humans: maintain conditions in the body
>
>
>
>
>
Temperature
pH
Water balance
Growth Development
• The hormone travels to a specific
site: the target cells have receptors
on them for this purpose
• Hypothalamus Gland:
> lower central part of the brain
> regulation of satiety, metabolism, and body temperature > secretes hormones that control the pituitary gland.
> Ex­ somatostatin­causes the pituitary gland to stop the release of growth hormone. 3
NOTES­ Endocrine System
• Pituitary Gland:
• base of the brain, no larger than a pea • control many functions of other endocrine glands > The anterior lobe –
–
–
–
Growth hormone Thyroid­stimulating hormone (TSH) Adrenocorticotropin hormone (ACTH) Luteinizing hormone (LH) and follicle­stimulating hormone (FSH) ­ control sexual function and production of the sex hormones
– Prolactin ­ stimulates milk production in females > The posterior lobe
– Antidiuretic hormone ­ Controls water loss by the kidneys
– Oxytocin ­ Contracts the uterus • Pineal Gland:
> middle of the brain > Melatonin: regulate the wake­sleep cycle
4
NOTES­ Endocrine System
• Thyroid Gland:
> lower front part of the neck
> thyroid hormones: regulate metabolism > bone growth and development of the brain and nervous system in children > maintain normal blood pressure, heart rate, digestion, muscle tone, and reproductive functions
• Parathyroid Gland:
> 2 pairs of small glands embedded in the surface of the thyroid gland
> parathyroid hormone: regulating calcium levels
• Adrenal Glands:
> located on top of each kidney « corticosteroids
» regulate the body’s metabolism, the balance of salt and water in the body, the immune system, and sexual function « produces hormones (eg, adrenaline)
» help the body cope with physical and emotional stress by increasing the heart rate and blood pressure.
5
NOTES­ Endocrine System
• Pancreas:
>
>
>
>
toward the back of the abdomen behind the stomach
digestive and hormonal functions digestive enzymes secretes hormones
– insulin and glucagon
regulate the level of glucose (sugar) in the blood
Comparing Control Systems
6
NOTES­ Endocrine System
Feedback Loops
Negative feedback­
Causes activity to turn off until the right level is reached (detects too much of something) [hormone regulation]
Positive feedback­
Causes an increase in activity until the right level is reached (detects too little of something) [contractions during child birth/
blood clotting]
7