BIO 202 Lab: Section 1.1-1.2: Endocrine System

Endocrine System

What hormones does the parathyroid glands produce and its function

Parathyroid hormone (PTH): the main hormone that maintains calcium ion homeostasis. It increases calcium levels and triggers osteoclast activity, bone resorption, increase calcium ion absorption from intestines, increased calcium ion reabsorption from kidneys

What are hormones like PTH and calcitonin considered to be

Antagoinsts

Where is the thymus gland located

Sits in the superior mediastinum

When is the thymus gland most active and what hormones does it secrete

It is large and active during infancy and early childhood, during which it secretes thymosin and thymopoietin

What does the hormones thymosin and thymopoietin stimulate in the thymus gland

Stimulate the development of T lymphocytes within the thymus gland

What happens to the thymic tissue in the thymus gland in adults

It gradually is replaced by fat and other connective tissue

Where is the adrenal gland located

Sits atop the superior pole of each kidney (ad: next to, renal: kidney)

What are the two structures of the adrenal gland

Outer adrenal cortex and inner adrenal medulla

What are the adrenal glands surrounded by

A thin layer of connective tissue called adrenal capsule

What type of hormones does the adrenal cortex secrete and derived from what

They secrete steroid hormones derived from cholestrol in response to stimulation by adrenocorticotropic hormone

What are the three zones of the adrenal cortex

Zona glomerulosa, zona fasciculata, zona reticularis (Zona GFR)

What type of steroid hormone does zona glomerulosa secrete and an example

Secretes mineralocorticoids. An example is aldosterone, which regulates fluid, electrolyte, and acid-based homeostasis (GMA)

What type of steroid hormone does zona fasciculata secrete and an example

Secretes glucocorticoids. An example is cortisol, which regulates stress response, blood glucose, fluid homeostasis, and inflammation

What type of steroid hormone does zona reticularis secrete and an example

Secrete gonadocorticoids and glucocorticoids. An example is androgens and estrogens, which affect the gonads and other tissues

What does the adrenal medulla consist of and what hormone does it secrete and derived from

Consist of modified postsynaptic sympathetic neurons that secrete the hormone adrenal catecholamines, which are derived from amino acids

What are examples of adrenal catecholamines in the adrenal gland

Norepinephrine and epinephrine, which prepares the body for stressful situations (sympathetic nervous system)

What effects does adrenal catecholamines have the same effect on target cells as and what are they

Neuronal catecholamines: dilation of bronchioles, increase rate and force of heart contraction, constriction of blood vessels serving skin and abdominal viscera, dilation of pupils

What does adrenal catecholamines do that neuronal catecholamines do not

Prolongs sympathetic response (neuronal catecholamines are terminated after a few seconds) and acts on target cells not innervated by sympathetic neurons

Where is the pancreas located and what type of functions does it do

Behind and below the stomach. It has both endocrine and exocrine functions

What carries out the exocrine functions in the pancreas and its function

Pancreatic acini or acinar cells that release pancreatic juices into pancreatic ducts. The pancreatic juices neutralize hydrochloric acid, digesting protein, fat, and starches

What carries out endocrine functions in the pancreas and its function

Pancreatic islets that is embedded into the pancreatic acini. Cells within pancreatic islet secrete insulin and glucagon which regulate blood glucose levels

What cells produce insulin and glucagon and its function

Insulin in secreted by beta (β) cells which helps lower glucose levels and glucagon is secreted by alpha (α) cells which helps increase glucose levels

Where is the testes located and what does it produce

Male reproductive organ located in the scrotum that produce sperm cells (male gametes)

What are the cells in the testes called and what steroid hormone does it produce and its function

Interstitial cells that produce testosterone, which promotes production of sperm cells and the development of male secondary sex characteristics (deep voice, greater bone, muscle mass, facial hair)

Where is the ovaries located and what does it produce

Female reproductive organs located in pelvic cavity that produce oocytes (female gametes)

What hormones does the ovaries produce and its function

Estrogen: plays a role in development of oocytes and female secondary sex characteristics (breast, subcutaneous fat stores) Progesterone: prepares the body for pregnancy

What type of histology slide is this showing and how do you know

Thyroid gland: simple cuboidal epithelium and colloid in middle

What type of histology slide is this showing and how do you know

Adrenal gland: the layers and capsule

What type of histology slide is this showing and how do you know

Pancreas: the pancreatic islets

What are exocrine glands and some examples

Glands that rely on ducts to release their substance. For example: sweat, salivary, lacrimal, digestive, mammary glands

What is the endocrine system

Diverse group of ductless glands that play a major role in maintaining homeostasis of multiple physiological variables

How does the endocrine and nervous system differ

The nervous system functions by action potentials and releases neurotransmitters that directly affect target cells. Effects are immediate but short in duration. Endocrine system secretes hormones that act on distant targets. Effects are not immediate but longer-lasting

Which endocrine glands secrete hormones as their primary functions

Thyroid and anterior pituitary glands

Which endocrine glands secrete hormones as their secondary function

The heart (atrial natriuretic peptide), adipose tissue (leptin), the kidneys (erythropoietin), and stomach (gastrin)

What type of system is the nervous and endocrine also referred to as

Nervous is referred to as our fast response system and endocrine system is our slow response system

Where is the hypothalamus located and what is it also known as

The inferior part of the diencephalon and is known as a neuroendocrine organ and the CEO of endocrine system

What is the endocrine system primary means of travel

Blood

What does the hypothalamus working closely with and how is it attached

Works closely with pituitary gland, which is attached by a stalk called infundibulum

What hormones does the hypothalamus produce that works with the anterior pituitary

Releasing and inhibiting hormones

How does the hypothalamus communicate with the anterior pituitary gland

Through the hypothalamic - hypophyseal portal system

What is another name for the 2 regions of the pituitary gland and what are they composed of

Anterior pituitary gland or adenohypophysis: composed of glandular epithelium Posterior pituitary gland or neurohypophysis: composed of nervous tissue

What is the pathway of the hypothalamic-hypophyseal portal system

The inhibiting and releasing hormones are synthesized by hypothalamic neurons -> then they enter hypothalamic capillary bed -> then they travel through the portal veins in infundibulum -> then they enter anterior pituitary capillary bed -> then they exit the blood

What hormones does the hypothalamus produce that works with the posterior pituitary and its functions

Oxytocin: uterine contraction and milk ejection from mammary glands Antidiuretic (ADH): causes water retention from kidneys and controls blood pressure

What hormones does the anterior pituitary gland produce (mostly tropic)

Follicle stimulating hormone: stimulates follicles in ovary & sustentacular cells in testes
Luteinizing hormone: stimulates oocytes in ovary & interstitial cells in testes Adrenocorticotropic hormone: stimulates secretion from adrenal cortex
Thyroid stimulating hormone: stimulates growth/secretion of thyroid gland Prolactin: stimulates milk production from mammary glands
Growth hormone: increases rate of cell division & protein synthesis; has both tropic/non-tropic effects (FLAT-PG)

What hormones does the posterior pituitary gland produce

They do not produce hormones, it stores oxytocin and antidiuretic hormone produced by hypothalamus

Where is the pineal gland located and what type of organ is it

In the posterior and superior diencephalon and is a neuroendocrine organ

What hormones does the pineal gland secrete and based on what

Melatonin in response to decreased light levels. This hormone acts on the reticular formation part of the brainstem to trigger sleep

How does follicle cells respond to TSH from anterior pituitary in thyroid gland

By secreting a chemical into the colloid that reacts with iodine to produce 2 hormones: thyroxine (T4) and triiodothyronine (T3)

Where is the thyroid gland located

Anterior-inferior neck, superficial to the larynx or voicebox

What does the thyroid gland consist of and how are they connected

Consist of left and right lobes connected by a thin band of tissue called isthmus

Describe what the thyroid gland is composed of

Composed of thyroid follicles that are lined with simple cuboidal follicle cells and encapsulates a colloid

What is between the follicle cells in the thyroid gland and its function

Parafollicular cells - it produces calcitonin which decreases blood calcium levels and triggers osteoblast activity and bone deposition

What is the function of triiodothyronine (T3) of the thyroid gland

It is the most active of the two hormones. It increases metabolic rate, protein synthesis, regulate heart rate and blood pressure. When T3 levels are low, T4 gets converted to T3