The Endocrine System (Chpt. 35 ) Flashcards
Gland
A structure that releases a product
Endocrine gland
Secretes hormones directly into the blood
→ ductless
Exocrine gland
Secretes its products into a duct
E.g. Salivary glands, sweat glands
Examples of exocrine glands
Salivary glands
Sweat glands
Nerve action VS Hormone action
NERVE
Message is electrical, impulses travel along nerve fibres to a specific cell/tissue, rapid transmission, brief action
HORMONE
Message is chemical, chemical messengers in the blood send message to many regions, slow transmission, long lasting action
Hormone
Chemical messenger produced by an endocrine gland and carried by the bloodstream to another part of the body where it has a specific effect
Types of hormones & examples p
Protein e.g. Insulin
Steroids (lipids) e.g. Reproductive hormones
How many major endocrine glands in body? Name them.
10
- Hypothalamus
- Pituitary
- Pineal
- Thyroid
- Parathyroids
- Thymus
- Adrenal
- Ovaries
- Testes
- Pancreas (islets of langerhans)
Name a gland that has an endocrine and exocrine function
Pancreas
Endocrine - insulin
Exocrine - digestive enzymes
Over production of a hormone (cause, symptoms, treatment)
Thyroxine
Enlarged thyroid - goitre
Hunger, bulging eyes, weight loss, anxiety
Surgery to remove part of thyroid
→ Graves’ disease
Hormone supplements (x2)
Insulin
Low insulin production - diabetes
Severe thirst, loss of weight, tiredness
Insulin injections
Thyroxine
Negative feedback
TSH - thyroid stimulating hormone
Normal concentration of thyroxine inhibits TSH production
Low concentration of thyroxine allows TSH to be made
Exocrine function of pancreas
Production of amylase / lipase
Explain insulin resistance
Cells become less sensitive to insulin
How does a response brought about by insulin differ from that brought about by a nerve action
Slower
Effect lasts longer
