endocrine system

Question 1

this system controls body activities by releasing mediators, which are called hormones.

Answer 1

endocrine system

Question 2

it is a signal molecules being released into a neighboring vascularised compartment for
uptake by capillaries and distribution throughout the body.

Answer 2

hormones
- could be
proteins (insulin or growth hormones)
lipid derivatives (steroids, amino acids - thyroid hormones)

Question 3

exocrine gland vs endocrine glands

Answer 3

Exocrine glands:
release their substances through ducts (like sweat glands or salivary glands).

Endocrine glands:
release their hormones directly into the bloodstream then travel through the body to reach their target organs or cells.

In short, while exocrine glands use ducts to release substances externally, endocrine glands send their secretions (hormones) into the blood to regulate internal processes.

Question 4

what are the primary and secondary endocrine system

Answer 4

➔ Primary Endocrine System
◆ Pineal gland
◆ Hypothalamus
◆ Pituitary gland

➔ Secondary Endocrine System
◆ Skin
◆ Heart
◆ Liver
◆ Stomach
◆ Kidney
◆ Intestines

Question 5

briefly explain the secondary endocrine system and its hormone it releases

Answer 5

◆ Skin
keratinocytes in the epidermis
- uses energy from sun cv rays
- to convert the cholesterol-like steroid into the inactive form of vitamin d3, cholecalciferol = enters the blood to the liver to bcm active form

◆ Heart
wall of cardiovascular tissue are endocrine cells
once it detects the increase in blood volume, the cells will release ANP, atrial natriuretic peptide

◆ Liver
- has various hormones and precursors of hormones
- cholecalciferol from the skin will
convert into calcidiol, which is the final step for vitamin b3 synthesis

• angiotensinogen: regulator for BP
• thrombopoietin: produced in liver, a hormone that stimulates the production of yr platelet
• erythropoietin (EPO): 15% of the production is coming from the liver.
  For the stimulation of RBC production
• insulin growth factor 1: regulates an action growth hormone that stimulates growth.
• hepcidin: inhibits the intestinal absorption of iron. helps regulate iron homeostasis to prevent
  iron overload.

◆ Stomach & Intestines
- peptide: signal the satiety signal to stop eating.
- ghrelin: releases when the stomach is empty to regulate the appetite.
- gastrin: releases in response to food and stomach to stimulate
HCI production.
- cholecystokinin, CCK: released
by the small intestine in response to fats and stimulates the release of enzymes from pancreas and bile from the gallbladder.

*once it is released, the pancreas must contribute its enzymes for the digestion of food

◆ Kidney
- calcidiol: from the liver, it will
convert into calcitriol, an active form of the vitamin d3.
- renin: is produced in response to dehydration or drop of BP

Question 6

what makes up the largest endocrine network as they release various hormones

Answer 6

stomach and intestine

Question 7

what type of cells are the walls of the cardiovascular tissues of the heart

Answer 7

endocrine cells

Question 8

this is being released when it detects the increase in blood
volume

Answer 8

ANP, atrial natriuretic peptide

Question 9

it is a regulator of BP

Answer 9

Angiotensinogen

Question 10

it is produced in the liver. a hormone that stimulates the production of your platelet.

Answer 10

Thrombopoietin

Question 11

how much of the production of EPO is coming from the liver

Answer 11

EPO
- for the stimulation of RBC production

Question 12

it regulates an action growth hormone that stimulates growth

Answer 12

Insulin growth factor 1

Question 13

it inhibits the intestinal absorption of iron. helps regulate iron homeostasis to prevent iron overload

Answer 13

Hepcidin

Question 14

it signal the satiety signal to stop
eating.

Answer 14

peptide

Question 15

it releases when the stomach is empty to regulate the appetite.

Answer 15

Ghrelin

Question 16

it releases in response to food and
stomach to stimulate HCI production.

Answer 16

Gastrin

Question 17

it is a hormone released by the small intestine in response to fats and stimulates the release of enzymes from pancreas and bile from the gallbladder

Answer 17

Cholecystokinin, CCK

Question 18

it is produced in response to dehydration or drop of blood pressure.

Answer 18

Renin

Question 19

briefly explain the secreting manner of endocrine system

Answer 19

Autocrine:
- “Self”
- Fr ex: cell is infected with SARS
COV 2. It secretes signals that act on itself to undergo apoptosis
- Helps kill viruses in the process

Juxtacrine:
- “Contact dependent/ cell to cell/ cell to ECM” (direct contact)
- Needs direct contact on cell or ECM.
- Fr ex: receptors need to be in contact with another cell.

Paracrine:
- Localized dispersal in interstitial fluid or through short loops of blood vessels.
- “Nearby”
- Fr ex: gap junction, the release of neurotransmitter during muscle contraction.

Endocrine:
- Cover of mostly endocrine glands.
○ They target a distant cell throughout the bloodstream.
○ Fr ex: pituitary gland going to thyroid gland. hence, needs to go through circulation.

Question 20

cells may produce molecules that act on themselves or on cells of the same type

Answer 20

autocrine

Question 21

a signaling molecules remains on the secreting cell’s surface or adjacent extracellular matrix and affects the target cells when the cells make contact

Answer 21

Juxtacrine

Question 22

localized dispersal in interstitial fluid or through short loops of blood vessels

Answer 22

paracrine

Question 23

it targets a distant cell through the bloodstream

Answer 23

endocrine

Question 24

briefly explain the components of endocrine system

Answer 24

● Hypothalamus
- control center of endocrine glands.

● Pancreas
- specifically the Islet of Langerhans.

● Pituitary
- second in command in the endocrine system.

● Thyroid
- responsible for the metabolic rate, protein synthesis and calcium metabolism.

● Parathyroid
- release parathyroid hormones, specifically for calcium levels.

● Adrenal
- located above your kidneys.

● Pineal
- for the sleeping patterns

● Ovaries and Testes

Question 25

A small part of the diencephalon is located at the base of the brain, behind the optic chiasm.

Answer 25

Hypothalamus - this part of the brain is important that links the endocrine and nervous system

Question 26

function of - hypothalamus - Neurohypophysis (Posterior Pituitary) - Adenohypophysis (Anterior Pituitary)

Answer 26

HYPOTHALAMUS Primary function: - maintain homeostasis or the instability of the internal environment in the body. - control numerous bodily functions (“control center/ chief in command”) ■ Thirst, hunger, temperature, sexual behavior, circadian rhythms NEUROHYPOPHYSIS - stores and releases hormones like ADH (antidiuretic hormone) and oxytocin. ADENOHYPOPHYSIS - produces various hormones that regulate multiple physiological processes (e.g., growth, metabolism, reproduction).

Question 27

what are the hormones that hypothalamus produces

Answer 27

Posterior pituitary Hypophysiotropic

Question 28

They are neuroendocrine cells that are located within the supraoptic nucleus and paraventricular nucleus.

Answer 28

Magnocellular Neurosecretory Neurons - produce the hormones oxytocin and ADH - transport them to the posterior pituitary for storage and later release into the bloodstream.

Question 29

what are the 2 types of neurosecretory cells in Magnocellular Neurosecretory Neurons

Answer 29

Oxytocin: - Oxytocin-producing - Stimulates contraction of smooth muscles in myometrium - uterine, distention. - Promotes transaction of milk during lactations in nipples. ADH, antidiuretic hormone: - Vasopressin-producing - Secretes in response to dehydration or blood loss. - Increase permeability of the distal and collecting tubules leading to the formation of the more concentrated urine. *they are stores in the hypothalamus, in the posterior pituitary [when the body needs them (like during childbirth or dehydration), the hormones are released into the bloodstream.]

Question 30

how does the hypothalamus control the anterior pituitary

Answer 30

- using parvocellular neurosecretory neurons - these neurons secrete hormones into a special network of blood vessels called thehypothalamus hypothetical system (or hypothalamo-pituitary portal systemin other reference)

Question 31

where does the Parvocellular Neurosecretory Neurons (PNNs) located

Answer 31

in the paraventricular nucleus of the hypothalamus. - PNNs release releasing hormones and inhibiting hormones that control the secretion of hormones from the anterior pituitary

Question 32

briefly explain the anterior pituitary cells and their hormones

Answer 32

(notes) Somatotrophs: - Growth Hormone (GH) - Stimulates body growth, regulates metabolism. Gonadotrophs: - Luteinizing Hormone (LH) - Follicle Stimulating Hormone (FSH) - Stimulates the gonads (ovaries and testes) to produce sex hormones. Lactotrophs: - Prolactin (PRL) - Stimulates milk production in the mammary glands. Corticotrophs: - Adrenocorticotropic Hormone (ACTH) - Stimulates the adrenal cortex to release cortisol and melanin. Thyrotrophs: - Thyroid Stimulating Hormone (TSH) - Stimulates the thyroid gland to release thyroid hormones (T3 and T4).

Question 33

briefly explain the hypothalamic releasing and inhibiting hormones

Answer 33

(notes) 1. Corticotropin-Releasing Hormone (CRH): - stimulates the release of ACTH from the corticotrophs - which then stimulates the adrenal glands to release cortisol. 2. Thyrotropin-Releasing Hormone (TRH): - stimulates thyrotrophs in the anterior pituitary to release TSH = affects the thyroid gland. 3. Growth Hormone-Releasing Hormone (GHRH): - akasomatocrinin - stimulates somatotrophs in the anterior pituitary to release growth hormone. 4. Growth Hormone-Inhibiting Hormone (GHIH): - aka somatostatin - it inhibits the release of growth hormone from somatotrophs in the anterior pituitary. 5. Gonadotropin-Releasing Hormone (GnRH): - acts on gonadotrophs in the anterior pituitary to release LH and FS then act on the gonads (ovaries/testes). 6. Prolactin-Inhibiting Hormone (PIH): - dopamine acts as PIH, inhibiting lactotrophs from releasing prolactin. - when dopamine is low, prolactin is secreted, stimulating milk production in mammary glands. *once the hormone is secreted by the Parvocellular Neurosecretory Neurons, it will produce a specific hormone based on the secretions of the Parvocellular neurons. It will then act on the target glands to release another specific hormone.

Question 34

briefly explain the process of hormone release and action in hypothalamus

Answer 34

1. Hormone Release by Parvocellular Neurosecretory Neurons: parvocellular neurosecretory neurons in the hypothalamus secrete specific releasing hormones or inhibiting hormones into the hypothalamo-pituitary portal system (a network of blood vessels). 2. Hormone Travels to the Anterior Pituitary: these hormones travel directly through the portal system to the anterior pituitary. 3. Anterior Pituitary Cells Respond: upon receiving the signals from the hypothalamic hormones, the anterior pituitary cells (e.g., somatotrophs, gonadotrophs, lactotrophs, etc.) either stimulate or inhibit the release of their own specific hormones. 4. Target Glands Respond: these anterior pituitary hormones then travel through the bloodstream to their target glands (e.g., thyroid gland, adrenal glands, gonads, mammary glands). 5. Target Glands Release Specific Hormones: once the anterior pituitary hormones reach the target glands, the target glands then release their own specific hormones to regulate various body functions [Example Process (Using Growth Hormone as an Example): Parvocellular Neurosecretory Neurons release Growth Hormone-Releasing Hormone (GHRH) in response to signals from the body (like growth needs). GHRH travels through the hypothalamo-pituitary portal system to the anterior pituitary. In the anterior pituitary, somatotrophs (cells that produce growth hormone) are stimulated by GHRH to release Growth Hormone (GH). Growth Hormone then travels to various target organs, such as the liver, muscles, and bones, where it promotes growth and regulates metabolism. Summary: The hypothalamus sends releasing hormones via the hypothalamo-pituitary portal system to the anterior pituitary. The anterior pituitary then releases specific tropic hormones that stimulate target glands (like the thyroid, adrenal glands, or gonads). These target glands release their own hormones that carry out important physiological functions in the body.]

Question 35

Magnocellular Neurosecretory Cells and Parvocellular Neurosecretory Cells - location - secretion

Answer 35

Posterior Pituitary (Neurohypophysis): Magnocellular Neurosecretory Cells: Location - in the periventricular and optic nuclei of the hypothalamus. Secretion - release hormones (oxytocin and ADH) into the posterior pituitary (also known as the pars nervosa). ---- stored un the posterior pituitary until the body receive the appropriate signal ---- when triggered, hormones released directly into the bloodstream from the posterior pituitary into the blood's circulation ---- hormones released: Oxytocin & ADH (Vasopressin) Anterior Pituitary (Adenohypophysis): Parvocellular Neurosecretory Cells: Location - in the paraventricular nucleus of the hypothalamus Secretion - parvocellular cells secrete releasing hormones or inhibiting hormones that regulate the anterior pituitary's hormone release. - these include corticotropin-releasing hormone (CRH), thyrotropin-releasing hormone (TRH), and growth hormone-releasing hormone (GHRH).

Question 36

briefly explain the Portal System Structure in the Hypothalamic Hypophyseal Portal System

Answer 36

consists of two main plexuses: Primary Plexus: - Located in the hypothalamus. Secondary Plexus: - Located in the anterior pituitary. Travel of Hormones: Hormones secreted by the parvocellular cells travel through the primary plexus, then move through portal vessels to the secondary plexus in the anterior pituitary.

Question 37

briefly explain the action on anterior pituitary cells - cell type - hormone secreted - target gland - effect

Answer 37

(notes) Somatotrophs: - Growth Hormone (GH) - Liver, muscles, bones - Stimulates growth and metabolism Gonadotrophs - Luteinizing Hormone (LH) & Follicle Stimulating Hormone (FSH) - Gonads (ovaries, testes) -Stimulates sex hormone production and gamete development Lactotrophs - Prolactin (PRL) - Mammary glands - Stimulates milk production Corticotrophs - Adrenocorticotropic Hormone (ACTH) - Adrenal cortex - Stimulates cortisol production Thyrotrophs - Thyroid Stimulating Hormone (TSH) - Thyroid gland - Stimulates thyroid hormone production

Question 38

posterior and anterior pituitary hormones

Answer 38

transes

Question 39

whats the weight of the pituitary gland and shape

Answer 39

an ovoid body that weighs merely 500 mg

Question 40

location of the pituitary gland

Answer 40

inferior surface of the hypothalamus

Question 41

what are the 2 distinct parts of the pituitary gland

Answer 41

Neurohypophysis (posterior): - derived from neural ectoderm. hence, more on nerve tissues as it acts as storage of oxytocin and vasopressin Adenohypophysis (anterior): - derived from oral ectoderm. hence, the structure is more epithelial. (5 cells)

Question 42

briefly explain the distinct structures of the anterior pituitary and the posterior pituitary

Answer 42

➔ Anterior Pituitary (Adenohypophysis): Pars Tuberalis Pars Intermedia Pars Distalis (Main Portion) - occupies the entire anterior portion - Ratke’s Pouch: * space in the middle of the pars distalis * an embryological structure that gives rise to the anterior pituitary. ➔ Posterior Pituitary (Neurohypophysis): Infundibular Stalk - has infundibulum and median eminence - occupies the entire posterior portion of the pituitary. !! Microscopic Appearance: Pars Distalis (Anterior Pituitary) - darker when viewed under the microscope due to the dense population of hormone-secreting cells. Pars Nervosa (Posterior Pituitary) - lighter under the microscope, as it mainly contains nerve fibers and is less cellular compared to the anterior pituitary.

Question 43

why is the posterior pituitary is more fibrous than cellular

Answer 43

as it is mainly stores and secretes hormone produced by the hypothalamus - not a gland, stores and releases hormones like ADH (antidiuretic hormone) and oxytocin.

Question 44

why is anterior pituitary is more cellular than fibrous

Answer 44

as it is actively involved in hormone production

Question 45

what are the 3 regions of the Pituitary Gland (Neurohypophysis)

Answer 45

Pituitary stalk ○ Infundibulum, Infundibular stem, Infundibular stalk, Hypophyseal stalk. Posterior Lobe ○ Pars nervosa, Infundibular process.

Question 46

Storage sites for the secretory granules

Answer 46

Dilatations of Magnocellular Secretory Neurons

Question 47

Aggregations of secretory granules; deeply- staining, basophilic structures.

Answer 47

Herring bodies - this is where the ADH and vasopressin is stored

Question 48

what surrounds the axons of secretory neurons

Answer 48

Pituicytes (stellate cells) - function: who assist the herring bodies for storage and release

Question 49

true or false: Pituicytes are the glial cells.

Answer 49

true - it is for support

Question 50

what are the 3 regions of the Pituitary Gland (Adenohypophysis)

Answer 50

Pars Distalis (Anterior lobe) Pars Tuberalis (Pars infundibularis) Pars Intermedia (Intermediate lobe)

Question 51

Comprise about 70% of the pituitary gland.

Answer 51

Pars Distalis - collectively referred to as anterior pituitary hormones

Question 52

what is the parenchyma of the - Pars Distalis - Pars Intermedia - Pars Tuberalis

Answer 52

PARS DISTALIS Secretory epithelial cells ★ What is the source that gives the secretion of the hormone? That is the parenchyma. ● Chromophils - 35% of parenchymal cells - Acidophil - pinkish, production of growth hormones or product team - Basophil - responsible for secretion of DSH, ACTH, FSH or luteinizing ● Chromophobes - 65% of parenchymal cells - They are undifferentiated or are your resting chromophils. - Pale staining. ★ Chromophils and chromophobes are classified based on their affinity for the standard histological dyes. PARS INTERMEDIA - Melanocytes Stimulating Hormone (MSH) and ß- endorphins ○ MSH produces melanocytes for melanin. ○ ß- endorphins produced in response to pain as it blocks the sensation of pain. PARS TUBERALIS ○ Gonadotrophs: Luteinizing hormone and follicle stimulating hormone for ovaries and testes. ○ Thyrotrophs: for TSH in the thyroid

Question 53

pineal gland aka

Answer 53

"pineal body" "epiphysis cerebri"

Question 54

pineal gland - shape - location - weigh - length

Answer 54

- small conical structure - attached to the posterior portion of the roof of the third ventricle of the brain - weigh abt 120mg - length abt 8mm

Question 55

parenchyma and stroma of - pineal gland - parathyroid gland

Answer 55

PINEAL GLAND Parenchyma: Pinealocytes Stroma: Interstitial cells PARATHYROID GLAND Parenchyma: - Chief cells or "Principal cells" non secretory no known function appear shortly before puberty and increase in no. w age - Oxyphil cells S or "Acidophil cells" compromise majority of the parenchymal cell - secretes PTH, Parathyroid Hormone which is the most mpt. regulator of blood calcium level

Question 56

what does it secretes - pineal gland - thyroid gland

Answer 56

PINEAL GLAND Secretes Melatonin - physiologic function is not yet known (speculations that it affects circadian rhythms and sleep patterns). - subjected for further studies - researchers says that melatonin is a hormone in your brain that produces and responds to darkness. hence, related to sleeping patterns which tells the body to sleep when there is no light. *called “third eye” in other references. THYROID GLAND - Thyroxine (14) - inactive form - Triiodothyronine (T3) - active form - Calcitonin

Question 57

“third eye”

Answer 57

pineal gland

Question 58

he called pineal gland as "seat of the soul"

Answer 58

Rene Descartes - a philosopher - believes that people have a body and soul. and a person won't be alive if there is no soul.

Question 59

A calcified bodies which has concentric lamellar structure which consists of calcium phosphates and carbonates.

Answer 59

brain sands - aka psammoma bodies - concentration of brain sand increases in age, it becomes visible among x rays.

Question 60

it acts as a landmark in physiological and anatomical examinations, especially in brain imaging.

Answer 60

pineal gland

Question 61

An unpaired gland that lies on the anterior aspect of the neck

Answer 61

thyroid gland

Question 62

largest endocrine gland

Answer 62

Thyroid Gland

Question 63

weight of thyroid gland

Answer 63

25 to 40g in weight and slightly bigger in women than in men

Question 64

what does thyroid gland consists of

Answer 64

2 lateral lobes (Right and Left) isthmus

Question 65

Secreted by thyroid gland which lowers down blood calcium levels.

Answer 65

Calcitonin

Question 66

briefly explain c- cell

Answer 66

- aka s "parafollicular cells" or "mitochondria rich cells" - Secretes calcitonin - Decrease calcium levels

Question 67

A homogenous, gel- like material where T3 and T4 is being formed

Answer 67

colloid

Question 68

briefly explain the function of principal cells in the thyroid gland

Answer 68

- aka "follicular cells" 1. Produce Thyroglobulin - a protein made inside the cells and released into the colloid (gel-like center of follicles). 2. Iodine Transport - these cells pull iodine from the blood and move it into the colloid. 3. Iodination -an enzyme called thyroid peroxidase helps stick iodine to tyrosine (an amino acid) on thyroglobulin. - this forms: MIT (Monoiodotyrosine) = 1 iodine DIT (Diiodotyrosine) = 2 iodines 4. Hormone Formation MIT + DIT = T3 (Triiodothyronine) DIT + DIT = T4 (Thyroxine) 5. Stimulation by TSH (Thyroid-Stimulating Hormone) - causes cells to bring the iodinated thyroglobulin back inside, break off T3 and T4, and release them into the blood. 6. Function of T3 & T4 - travel through the blood and regulate metabolism (how fast your body uses energy).

Question 69

parathyroid gland - shape - color - location

Answer 69

- 2 pairs (Superior and Inferior) of yellowish-brown, tiny, ovoid bodies - attached to the posterior surface of the lateral lobes of the thyroid gland

Question 70

adrenal gland - aka - shape

Answer 70

- aka "Suprarenal gland" - paired adrenal gland that are flat, pyramidal organs that rest on the upper pole of kidneys.

Question 71

what are the 2 regions of the adrenal gland

Answer 71

1. Cortex - surrounds the medulla 2. Medulla - inner part ■ Outer - zona glomerulosa - 15% of adrenal cortex - responsible for androgen (testosterone and estrogen). - produce mineralocorticoids, specifically aldosterone ■ Middle - zona fasciculata - 80% of adrenal cortex - has spongiocytes, foamy cytoplam - producing corticoids and corticosterone which regulates carbs, lipid and protein metabolism. - consists of glucocorticoids ■ Inner - zona reticularis - 7%of the adrenal cortex - responsible for the dehydroepiandrosterone (DHEA), which produce hormones such as testosterone and estrogen. - also androstenedione is a promoter of a protein metabolism and growth - responsible for the release of non-mineralocorticoids

Question 72

this cells secretes catecholamines

Answer 72

chromaffin cells - aka pheochromocytes (fight or fligt hormones

Question 73

what are the 4 distinct cell types in the pancreas (Islet of Langerhans)

Answer 73

● A cells (a- cells): Large cells that occupy the peripheral areas of the islet. - secretes glucagon that increases the blood glucose level. ● B cells (β- cells): Smallest but most numerous, located in the central area of the islet. - secretes insulin which involves facilitating the entry of the glucose cells. ● D cells (δ- cells): Largest and scattered singly over the islets. - secrets somatostatin, where the main action is on the secretion of other cells. ● F cells (PP cells): Rare and widely scattered. - secretes pancreatic polypeptide which slows down the absorption of food from the intestines