Module 7 Flashcards
Endocrine
Cells of these glands secrete hormones directly into the interstitial fluid surrounding the secretory cells, the hormones are then picked up by blood capillaries
Exocrine
Glands that secrete cell products into a duct system
Hormones
Act as chemical messengers, traveling through the blood circulation to cause an effect on a target
Pituitary Gland
small gland at the base of the brain that extends from the hypothalamus. It is known as the master gland as it produces and releases hormones that control all endocrine glands
Thyroid Gland
Sits anterior to the trachea and produces thyroid hormones for regulating metabolism
Parathyroid Gland
Small glands situated on the back of the thyroid gland, they are paired, two superior and two inferior. They are involved in maintaining calcium homeostasis
Adernal Glands
They are on top of the kidneys. There are two parts the cortex and the medulla. They have important roles in the production of corticosteroids and maintence of fluid balance.
Corticosteroids
Steroid hormones produced by the cortex of the adrenal gland that are responsible for glucose metabolism, sex characteristics and electrolyte balance of body fluids
Pituitary Gland
It is known as the master gland because it releases hormones that control all other endocrine glands
Where is the Pituitary Gland Located?
Inferior to the hypothalamus and sits on a concavity of the sphenoid bone in the middle of the skull
What Systems Does the Pituitary Gland Communicate With?
Physical contact between the hypothalamus and pituitary gland allows for communication between the nervous and endocrine system
Lobes of the Pituitary Gland
It has two lobes: anterior (adenohypophysis) and posterior (neurohypophysis)
Anterior Lobe (Adenohypophysis)
Composed of glandular (andeno) secretory cells that produce and release 7 stimulating hormones
Seven Stimulating Hormones of the Anterior Lobe
- Thyroid Stimulating Hormone (TSH)
- Prolactin (PRL)
- Adrenocorticotropic (ACTH)
- Growth Hormones (GH)
- Follicle Stimulating Hormone (FSH)
- Luteinizing Hormone (LH)
- Melanocyte Stimulating Hormone (MSH)
Thyroid Stimulating Hormone (TSH)
TSH released from the anterior pituitary acts on the thyroid gland, causing it to release thyroid hormones
Prolactin (PRL)
Includes mammary glands of the breast to produce milk
Adrenocorticotropic (ACTH)
Released by the anterior pituitary gland acts on adrenal glands causing them to release their hormones
Growth Hormones (GH)
Stimulates growth in all cells
Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH)
FSH and LH both act on the gonads: they stimulate secretion of estrogen and progesterone, and maturation of oocytes in the ovaries, and they stimulate secretion of testosterone and sperm production in the testes
Melanocyte Stimulating Hormone (MSH)
Stimulates melanocytes in the skin to produce pigment
Posterior Lobe (Neurohypophysis)
The posterior lobe of the pituitary gland is also known as the neurohypophysis because it is made up of nervous tissue.
It only releases two hormones. These hormones are produced in the hypothalamus
Hormones Released by the Posterior Lobe
Antidiuretic Hormone (ADH) and Oxytocin
Antidiuretic Hormone (ADH)
Promotes reabsorption of water at the kidneys
Oxytocin
Promotes uterine contractions during childbirth and also plays a role in breastfeeding
What is the Posterior Lobe Made up of? - Pituitary Gland
Nervous and connective tissue, and does not contain acini
What is the Anterior Lobe Made up of? - Pituitary Gland
Glandular acini (small saclike cavities) that are arranged in small groups, surrounded by connective tissue
How is the Thyroid Divided up?
Into three anatomical structures
1. Right lobe
2. Left lobe
3. Isthmus, which sits between and connects the two lobes
Histology of the Thyroid
Composed of many structures called follicles. Each follicle is lined with simple cuboidal follicular cells that surround a central lumen filled with colloid. Dispersed between the follicles are parafollicular or C cells
Colloid Fluid
Protein rich fluid secreted by the follicular cells of the thyroid gland
Follicular Cells - Thyroid
Simple cuboidal cells surrounding each follicle. They produce Triiodothyronine (T3) and Thyroxine (T4), which act to increase the rate of metabolism and oxygen consumption
C Cells
Important in calcium homeostasis. They produce calcitonin a hormone which lowers the blood calcium concentration
Histology of Parathyroid Glands
They are mostly made up of principal (or chief) cells. Principle cells produce parathyroid hormone (PTH) which acts to increase calcium ion concentration in the blood
What Can the Adrenal Glands be Divided Into?
The medulla and the cortex. each produces different hormones
Cortex - Adrenal Glands
It is divided into three layers. These layers produce over two dozen hormones, collectively called corticosteroids.
What Hormone Does the Outer Layer of the Cortex Produce? (adrenal glands)
Mineralocorticoids
What Hormone Does the Middle Layer of the Cortex Produce? (adrenal glands)
Glucocorticoids
What Hormone Does the Inner Layer of the Cortex Produce? (adrenal glands)
Androgens (sex hormones)
Medulla - Adrenal Glands
The medulla is the core of the adrenal gland. It produces epinephrine and norepinephrine in response to sympathetic nervous system stimulation resulting in an autonomic (fight or flight) response.
Pancreas - Where and What is it
The pancreas is a long lobular organ that lies posterior to the stomach, with its medial end (head) reaching the duodenum and the lateral end (tail) extending to the spleen.
What Does the Pancreas do?
The pancreas produces enzymes for digestion and the hormone insulin that regulates blood sugar levels
Histology of the Pancreas
The pancreas is a mixed gland, it has both exocrine and endocrine functions
Endocrine Cells of the Pancreas
Endocrine functions in the pancreas are the result of specialized group of cells in the pancreatic islets or islets of Langerhans
What are the Two Main Cell Types of Pancreatic Islets?
Alpha and Beta
Functions of Alpha Cells
Produce glucagon, a hormone that functions to increase blood glucose level (hyperglycemic
hormone)
Functions of Beta Cells
Beta cells produce the hormone insulin, which functions to lower blood glucose levels (hypoglycemic hormone)
