Lecture 25. Endocrine Regulation of Physiological Function Flashcards
What are the five types of cell to cell communication ?
- Endocrine signaling
- Paracrine signaling
- Autocrine signaling
- Synaptic signaling
- Neuroendocrine signaling
What are hormones ?
Chemical signals secreted into the circulatory system that communicate regulatory messages to target cells
What are the three classes of hormones ?
- Polypeptides
- Steroids
- Amines
What are the water soluble hormones ?
- Polypeptides
2. Most amines
What hormones are lipid soluble ?
- Steroid hormones
2. Largely non-polar hormones
How are water soluble hormones secreted by ?
Exocytosis
What do water soluble hormones do ?
Travel freely in the bloodstream and bind to cell surface receptors
What do lipid soluble hormones do ?
Diffuse across cell membranes, travel in the bloodstream bound to transport proteins and diffuse through the membranes of target cell
Where do lipid soluble hormones bind ?
Receptors in the cytoplasm or nucleus of the target cells
Where are endocrine cells often grouped ?
Endocrine glands
What are endocrine glands ?
Ductless glands
What are some examples of endocrine glands ?
- Thyroid and parathyroid glands
2. Testes or ovaries
What do exocrine glands have ?
Ducts to carry secreted substances onto body surfaces or into body cavities
What is an example of an exocrine gland ?
Salivary gland
What does homeostasis in animal rely on ?
Negative feedback
What does negative feedback do ?
Helps to return a variable to a normal range
What are some examples of negative feedback ?
- Temperature regulation
2. Blood glucose regulation
What is positive feedback ?
Amplifies a stimulus and only contributes to homeostasis in animals in a small number of functions
What are some examples of positive feedback ?
- Childbirth
- Blood clotting
- Electrical impulses in nerves
What is feedforward ?
Anticipatory response to expected change
What are some examples of feedforward ?
- Increased heart rate in anticipation of exercise
- Increased secretion of insulin before food is digested to yield glucose
- Stimulation of gastric secretions due to thought/smell of food
What are hormones assembles into ?
Regulatory pathways
What integrates function of the endocrine system and the nervous system ?
The brain
What is the function of the hypothalamus ?
Coordinates electrical signaling
How does the hypothalamus coordinate endocrine signaling ?
Receives information from the nerves throughout the body and initiates appropriate neuroendocrine signals
What is the pituitary gland composed of ?
- Posterior pituitary
2. Anterior pituitary
What is the function of the posterior pituitary ?
Stores and secretes hormones that are made in the hypothalamus
What is the neural link also known as ?
Neurohypophysis
What is the function of the anterior pituitary ?
Makes and releases hormones under regulation of the hypothalamus
What type of link does the posterior pituitary have ?
Neural link