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Human Body > Histology #8 (Endocrine) > Flashcards

Histology #8 (Endocrine) Flashcards

1
Q

Hypothlumus

A

Location - In the brain between the thalumus and the pituitary halnd

Function -
1. Connects the nervous and endocrine systems
2. Receives signals input from many brain regions
3. Endocrine control center for maintaining homoestasis (monitors body for homoestasis)
- Releases hromones for antrior pititary regulation (releases hormones that act on the pituitary–> pituitary then releases hormones to effect organ)
- Produces ADH and oxytocin (released in the posterior pittutary)

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2
Q

Hypothelumus feedback + function

A

Overall - signals the pitutary gland to then release or inhibit its own hormones

Modultes a broad range of boldily functions to mainatin homeostasis:
1. Body tempertre
2. Blod pressure
3. Hunger and thirst
4. Sense of fullness when eating
5. MOod
6. Sex drive
7. Sleep

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3
Q

Hypotheliumus histology

A

Hypothelumus is connected directly to the posterior pituitray and the highly ceullarluzed antiorir pitutary

Image – see hypothelumus at the top ; bottom is the pituitray - connected by the pituitary stalk

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4
Q

Pituitary gland

A

Secretes hormones that have a direct/indirect effect on many other endocrine glands

Made up of two lobes:
1. Antior lobe (adenophypophis) –> Hypothelimis Hypohysea portal system
2. Posterior love (neurophypophis) –> Hypothalamic-Hypophyseal tract

Image - axons and tracts of nerves come into the posterior lobe ; antrior lobe is only a network of blood vessels

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5
Q

Pituitary gland Antioior lobe

A

Composed of:
1. Par Tuberalis
- Cuboidal epithelial
- hypophyseal portal vessles
2. Pars intermedia
- Cuboidal epithelium
- Layer of tissue filled with Coilloid-filled cysts
3. Pars distalis
- Cells arraged in thcik cords bordering on sinusiidal capilaries (allows cells to secrete hormones to capialries)
- Secretes the majority of hormones
- Largest region

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6
Q

Pituitary gland Antioior lobe staining

A

Chrompahil = cell that stains easily with dyes (in antrior lobe)

Types of cells in Antrior lobe:
1. Acidophiles (stains PINK) - growth hormone + prolactin
2. Basophils (stains PRUPLE) - Corticotrophin + Thryroid stimulating hormone + Follicle stimulating hromone + Letinizing hromeon

Have Fenetrated capilaries (in antior lobe)

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7
Q

Pituitary gland Antioior lobe staining - IMAGE 2

A

Pink arroes = Acidophils

Purple Arrows = Basophils

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8
Q

Pituitray galnd - Anteiror Lobe Secretions

A

Secretes:
1. Growth hormone - promotes body growth + targets growth plate in bone
2. Prolactine = Development of mmamry galnd during pregancey + stimulates milk production
3. Corticotrophin (ACTH) - stimulates adrenal cortext to produce glucocoticoids
4. Thyrodi stimulate homrone - Stimulates synethsis + secretion of thryoid hormones
5. Follicle stimulating Hormone - Promotes ovarian grwth/secretion of estrogen + promotes spermogensis/secretion of androgen binding protein
6. Liteinzing hromone - induce ovulation + stimultes testes (leydig cells) to synthesize and release testrone

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9
Q

Pituitray galnd - Posterior Lobe

A

Made up of 2 sections:
1. Infundibulum (pititray stalk)
- Contains non-mylinated axons
2. Pars Nervosa
- Conatins non-mylinated axons + has fenestrated capilaries + secretes hormones

Secrets:
1. Oxytosin - Contraction in birth + breast feeding
2. ADH - arterial constriction + water balance

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10
Q

Cells pituitray gland - posterior lobe

A
  1. Contains non-mylinated axons (nuerosecretry cells)
    - Cell bodies are located in the hypothlumus ; only axons in posterior lobe
  2. Contains supports glial cells (Pituicytes)
  3. Fenestrated capilaries

IMAGE - See non-mylinated axons + see the supporting glial cells

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11
Q

Hemeostatsis regulation by the hypothlumys

A

Overall - Hypotheumus = a control center that uses isgnlas form the body to monitor and mianatin homeostasis

Uses Negative feedback

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12
Q

Negative Feedback

A

Regulatory mechanism whose output decreases the processes that led to that output
- Helps maintain stabilized sytsem and steady state
- Autoregulation

Image - have detection by the hypothelumus –> respond to released hromone –> go to pituary –> pituitray releases hromone –> hormone goes to effect –> hypothlymus sees wehn we are in homoestsis –> stop secreting hormones

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13
Q

Hypothalamic-Pituitray-Adrenal Axis (Feedback)

A
  1. Detect stress
  2. Respond - Hypothelimic sees tress and releases CRH –> casues Pititratu release of ACTH
  3. Hormones effect organ - ACTH causes the adrenal gland releases cortisol (increases BP + increase glucose)
  4. Feedback - Negative feedback to the hypothelumus and pititary gland to slow the release of CRH and ACTH
    - Hypothlumus see sincrease in cortisol in blood –> slows down and stops cyle

Result - Autoregulated temperary response to a stessful event

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14
Q

Thyroid gland

A

Singe bilobed endocrine gland

Location - Antior to the tachea ; inferior to the larynx

Covering:
1. True capsule - fibroelastic connective tissue
2. False capsue - Pre-tracheal layer of cervical fascia

Structural and functional units = Thryoid follciles –> made up of Follcicular cels + Parafolicular cells + basemment memebrane

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15
Q

Thyroid gland Folicular cells

A

Overal - follicular cells line the thyroid follicle
- Rest of the basement membrane

Vary in size

Simple squmous = metabolically inactive

Simple cuboidal = metabolicaly active

Lumen formed by cell is filled with geltnous coloid
- Colloid is made by glycoprotein thyroglobulin
- Colloid is Acidophilic (stains PAS positive)

Image - shows PAS ; arrow shows colloid

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16
Q

Thyroid gland Folicular cells histology #2

A

See Folicular cells + coiloid

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17
Q

Thyroid Gland Parafoliclar cells

A

Parafoliclar cells = Distrubuted between follcicular cells and the basement membrane

Large + polyhedral + pale staining cells
- Oval + Eccentric nuceli

Function - Secretes calcitonin –> maintains calcium homeostasis

Can stain with IHC - stain for cacitonins = can see parafoliclaular cells

Image - see colloid + folicul;ar + parafolcilar cells

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18
Q

Thryoid function

A

Overall - Increases cellular metabolsim
- Increases respiration + thermogensis –> increases oxygen consumption + heat + basal metabolic rate

Acts on neary all systems (cardio + pulinary + nervous)

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19
Q

Thryoid function on cardiovascular

A

Icreases mycoadial intracceular calcium –> increases muclar contraction force and speed –> increases stoke volume + CO +HR

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20
Q

Thryoid function on Pulimary

A

Increases respiration rate + increases erthropoeitin/hemoglobulin –> increases oxygen delivery

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21
Q

Thryoid function on nervous

A

Increases wakefulness + alternternns in CNS

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22
Q

Thyroid Hormone from folicular cells

A

Folluclular Cells secerte:
T3 (triiodothryionine)- Active hormone

T4 (thryxine) - Less active form
- converted to T3 by type I (periphery) or type II (CNS) deionidases)

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23
Q

Thyroid Hormone from parafolliclar cells

A

Parafolliclar cells secrete:
Calcitonin - Oposses aarthryoid parathyroid hromone –> decreases blood calcium level

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24
Q

Synthesis fo Thryoid Hormones

A

DON’T memorize

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25
Q

Regulation of Thyroid Hormones

A

T3 and T4 = uses a nagetive feedback loop

  1. Thryoid releasing hromone producded in the hypothelymus
  2. TRH stimulates the release of thyroid of TSH
  3. TSH triggers secretion of T3 and T4
  4. T3 and T4 inhibit section of TSH by acting on hypothelumys and pitutitary

Calcitonin regulated by level of blood calcium
- Higher blood caclium = greater secretion

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26
Q

Parathyroid

A

LOOK AT OWN SLDIES

27
Q

Adrenal Glands

A

Location - On top of each kidney

Two regions - Corext + Medula

Functions:
1. Maintains water and Na homeostasysis
2. Control Blood presure
3. Regulate body’s adative stress resonse

28
Q

Adrenal Coretxt

A

Overall - produces steroid hrpmones

Cells = aranged in a cord-like manner within a widespread capilary network

Corext = devided into three zones
1. Zona Glamerulosa
2. Zona Fasciculata
3. Zona reticularis

29
Q

Adrenal Coretxt Zona glomerulso

A

Outter zone

Composed of closley packed rounded/arched cords of columnary or pyridmidal cells with many capilaries

15% of total glandular volume

Main secretory product - Aldostrone

30
Q

Aldostrone

A

Mineralcorticoid

Regulates electroplye and water balance and blood pressure

31
Q

Adrenal Coretxt Zona Fasciulata

A

Middle zone

Long straight cords of large cuboidal cells seperated by capialries

Cells have lipid droplets - appear vacuolated in image

75-80% of total glandular volume

Main secretroy product - cortisol + small amounts of weak andorgens

32
Q

Cortisol

A

Gluccocotrid - increases blood glucose levels + modulates cytokine products + anti-inflmaatory effect

33
Q

Adrenal Coretxt Zona Reticularis

A

Inner zone

Narrow dense layer of smaller cells arranged in a netwokr on irregular cords

Cells more heavily stains than in other zones (because have fewer lipid dorplets and more lipfusin pigement)

7% of glandular volume

Main secretory producy DHEA + Small amounts of gluccoticoids

34
Q

DHEA

A

Weak androgen

Converted to testrone in males and females

35
Q

Three zones in adrenal Corext

A
36
Q

Three zones in adrenal Corext Image #2

A
37
Q

Adrenal medulla

A

Function - Produces stress hormones to inituate fight/flught response

Inner part of adrenal gland

38
Q

Adrenal medulla histology

A
39
Q

Adrenal medulla hormones sectresion

A

Secretes catacholmines –> sceretes Epinephrine + norepinephrine

40
Q

Catcholamine secretion

A

Catcholamine secretion is upregulated during fear + stress + trauma

41
Q

Example Fight or flight

A

Tiger chasing you –> actuvates the stress sytem (sympathetic nervous system activation) –> Adrenal gland secretes catecholimines –> Body reacts to hormone signaling

42
Q

Epinephrine vs. Norepinephrine

A

Epineprhin - ONLy made by teh adrenal medulla (hormone)

Norepinephrine - Made by the sympathtic nervous system and the adrenal medulla (neurotranmitter + hormone)

43
Q

Goiter

A

Overall - Irregular growth of the thryoid
- Non-cancerous enlargment of the thyroid

Symptoms - Swelling nech + nodules in thryoid + diffculties swallowing + horse voice

44
Q

Goiter causes

A

Goiter causes:
1. Iodine deficney - iodine is needs to make thyroid hromones –> no iodine.= thyroid is bigger because make more cells to try and make more thryoid hormone
2. Graves (Hyperthyroidsm) –> Thryoid follicles make more TSH = more thryoid hromone
3. Hashimotos (Hypothyrodism)
- Autoimmune attack of thyroid gland –> no thryoid hromone production
4. Thyroditus
5. Thyroid cancer
6. Pregnacey - hCG made in preganncey mimic TSH = causes thyroid to make more thyroid hromone

45
Q

Graves vs. hashimotos

A

Graves - AB targets TSH = make more hromone

Hashimotos = AB targets thyroid gland cells = get cell death = make less hormone

46
Q

Goiter Histology

A

Left - normal

Right - englargment of follicle

47
Q

Types of goiter

A
  1. Colloid Goiter (endemic) - only in several areas
    • Happens with iodine defincey
  2. Non-txic goiter
  3. Toxic - caused by hypo/hyperthryodism
  4. Nodular goiter
  5. Multinodular goiter
48
Q

Risk factors for goiter

A

Living in area where iodine containing foods are in short supply

Obesity

Insulin resistence

Metabolic syndorme

Exposed to radiation on neck

Family history of thyroid disease

Being female and pregenant

Age

49
Q

Goiter diagnosis and treatment

A

Ultra sound + blood tests (anti-TPO and anti-TG) + biodpsy (tests for cancer) + thryoid scan + CT scan or MRI

Treatment - medication + surgery + radioactive iodine
- Medication for hypothyrodism (give thyroid hormone)
- If beccomes too large = can be painful –> could become cancerous –> have surgery to remove thryoid gland
- Can give radioactive iodine to kill thryoid gland

50
Q

Addison’s disease

A

Adrenal cortext doesn’t produce enough glucocorticois and minocortocids (adrenal insufficney)
- Zona fosiolata = secretes glucoocortocoids
- Glucocorticois + Minocortocids Hormones = regulate BP + eletolights + stress
- Have low Cortocoids

Causes - autoimmune attcj on adrenal cortext
- Can also stem from hemerapge + tumor + infection

51
Q

Addison’s disease histology

A

Left - nromal

right - Disease – layer is thin + plasma infiltration + lymphocytes infiltration

52
Q

Addison’s disease symptoms

A

Hyperpigmentaion of skin and mucocous membranes (Ex. JFK)

Poor apetite and wight loss

Low BP

GI upset

High cravings for salty foods

53
Q

Addison’s disease treatment

A

Treatment - pateints receive lifelong sterioid hormone replacment therapies + must take more cortisol if pateint has perioidic episodes of illness

54
Q

Pititary Ademona Classification

A
  1. Based on size
  2. Based on function
55
Q

Pititary Ademona Classification (size)

A

Smallest - microadenoma –> macroadenima –> giant tumors

MRI - see a ginat tumor (goes to optic chiasm)

56
Q

Pititary Ademona Classification (function)

A
  1. Non-functioning - effects non-sectroy cells –> No increase in hormone BUT still has secondary effects
    - Can cause blindness (optic interferance) + hypopituitrims (compression on nearby secretory cells) + headches/naseua (because increase intercranial pressure)
  2. Functioning/secrting - neoplasm of cells that can scerete hormones in pituitray
    - Causes hyerpitutarism (high hormone level)
57
Q

Pituitray adenomas stats

A

10% of people develope pituitary adenomas
- Micro = most common –> very minmal role in health = negligible effects on pateints

40% of pituitary adenimasl are non-functional

40% of pitutitary adenomas are prolactinomas –> tumors that secrete prolactin hormone

58
Q

Prolactinoma

A

Cancer of lctatrophes (lactatrphes make prolactin)

Most common form of pituitray adenocracinma
- Type of secreting adenoma

Effects nearly all organss

Prolactin signlaing is espcially prominent during pregnacey and lactation

Hyperprolactinemia = assocuated with obseity + insulin resistnce + non-alchol fatty liver disease

59
Q

Prolactinoma Diagnosis

A

Left - giant tumor –> right is removal of tumor after surgery

Most common treatment = surgery

60
Q

Prolactinoma Histology

A

NOT in image BUT can use IHC on functional tumors (Ex. stain for prolactin)
- Use IHC for the hormone being secreted to see caner invasion

Bottom of image = high cell count

Right = Somatatroph adenima –> see more cells in the bottom section compared to normal pituitary

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Human Body (31 decks)

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