A&P Chp. 16
The synthesis and release of most hormones are regulated by _________.
negative feedback system. **** Figure 16.5 in book****
What are the 3 types of endocrine gland stimuli to manufacture and release their hormones?
1) Humoral - remember body fluids or bloodborne chemicals (ie: Ca levels in blood) 2) Neural - neural fibers stimulate hormone release (catecholamines during times of stress) 3) Hormonal - endocrine glands release their hormones in response to hormones produced by other endocrine organs. (hypothalamic-pituitary-target endocrine organ feedback loop - core of endocrinology)
The parathyroid gland has 2 cells visible under microscopy.
1. chief cells - synthesize PTH, abundant purple/blue cells 2. oxyphil cells - unknown function, larger and clear around the outside.
Where is the adrenal glands located?
Above the kidney, literally attached to the kidney. ***Renal = kidney***
What 2 cells are responsible for hormone production in the pituitary gland?
Acidophil - GH and Prolactin Basophil - tropic hormones, TSH, ACTH, FSH, LH
Where is the Thyroid gland located?
Butterfly shaped, largest pure endocrine gland in the body, located in the anterior neck, on the trachea, inferior to the larynx.
Another name for pituitary gland
Hypophysis
What are general actions of the pineal gland?
Melatonin, hormone that controls diurnal cycle. Peaks at night (drowsy), lowest levels around noon.
How do hormonal vs. neural controls of body functioning differ?
Neural controls travel via electrochemical impulses that can be delivered by neurons in milliseconds. Hormone controls can take many seconds to days to reach target organs.
This gland has visible "zones" under microscopy
The adrenal gland, which makes sense because this gland has an outer layer and a deeper layer where the steroid hormones are produces.
Where is the parathyroid gland located?
There are usually 4, tiny, yellow- brown glands posterior of the thyroid gland.
Often called the "master endocrine gland"
anterior pituitary
Where is the hypothalamus located?
brain
What is a tropic hormone? And examples of tropic hormones are....
- A hormone that stimulates its target organ, which is also an endocrine gland, to secrete its hormone. - FSH and LH (stimulate gonad activities, ovaries and testes), ACTH (regulates adrenal gland activity), TSH (growth and activity of thyroid)
Pituitary Gland Location
- Connected to the hypothalamus - Has 2 lobes, the posterior lobe (actually part of the brain) and the anterior lobe
What are some differences between the endocrine and exocrine systems?
- Endocrine glands are ductless glands that secrete hormones into extracellular space the into blood or lymphatic tissue, while exocrine glands have ducts that transport secretions to the epithelial surface.
General actions of the thyroid gland
- Except for the brain, spleen, testes, uterus, and thyroid gland itself, TH affects virtually every cell in the body. - It's the bodies major metabolic hormone - Increases metabolic rate and body heat production. - maintains blood pressure - regulator of tissue growth and development - critical for development and maturation for reproductive capabilities - Also produces Calcitonin, decreases blood Ca levels...antagonistic to parathyroid gland hormones.
Where are the "islets of Langerhans" located. What 2 types of cells are found here?
- In the pancreas. - Alpha cells - produce glucagon - Beta cells - produce insulin
What are general actions of the parathyroid gland?
- It secretes PTH (parathyroid hormone), which is the single most important hormone controlling the CA+ balance in the blood. - When Ca levels are low, PTH goes to 3 target organs: skeleton, kidneys, and intestine
Hormones released by Posterior Pituitary
- Oxytocin - stimulates uterine contractions, labor - Antidiuretic hormone (ADH) or Vasopressin - important for water conservation
What are the general actions of the hypothalamus?
- Regulates hormonal output of the anterior pituitary - Synthesizes hormones that it exports to the posterior pituitary for storage. ****See figure 16.6****
Pituitary Gland General Action
- Secretes at least 9 hormones - The posterior lobe is composed of neural tissue and releases neurohormones received from hypothalamus. It's more of a hormone storage area. - The anterior lobe is composed of glandular tissue and releases a number of hormones.
This gland has visible nerve fibers under microscopy and these cells.
- The posterior pituitary - Pituicytes
Some hormones released by Anterior Pituitary
-Growth Hormone (GH) -Thyroid Stimulating Hormone (TSH) - ACTH - Cushing's disease - Follicle-stimulating hormone (FSH) - hyposecretion = failure of sexual maturation - Luteinizing hormone (LH) - production of estrogen/progesterone and testosterone - Prolactin (PRL) - lactation
What is the general action of the pancreas?
-Produces enzyme rich juice that is secreted into small intestine during digestion. - Production of glucagon and insulin
What are general actions of the adrenal glands?
-The inner adrenal medulla is part of the sympathetic nervous system, synthesized catecholamines (epinephrine, norepinephrine)...fight or flight response. - The outer adrenal cortex forms the bulk of the gland, synthesizes corticosteroids (ie: Aldosterone, Cortisol, Testosterone) - Both regions produce their own hormones, but all of them help us cope with stressful situations.
Where is the thymus gland located?
Deep behind the sternum, in the thorax. Decreases in size as we age.
Under microscope, the thyroid gland has 2 types of cells, the ____ and _____.
Follicle cells (small, purple) an Colloid filled follicles (large and pink)
Where is the pancreas located?
Partially behind the stomach
Where is the pineal gland?
Pine- coned shaped in diencephalon (brain)
What is the general action of the thymus?
Production of T-lymphocytes; immune response
Which glands are purely endocrine and which are mixed.
Pure endocrine - anterior pituitary, thyroid, adrenals, parathyroid Mixed - pancreas and gonads (meaning these are both endocrine and exocrine)
