L5- Glands introduction Flashcards

1
Q

definition of a gland

A

‘An epithelial cell or an aggregate of epithelial cells that are specialised for the secretion of a substance’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

secretion

A

production and release of materials by a cell or aggregate of cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

types of gland

A

endocrine and exocrine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

glands are typically classified according to

A

their structure and how the products are released

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

endocrine

A

ductless

  • secrete directly into the blood flowing through them
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

exocrine

A

ducted

  • secrete into a location or region of the body through a duct
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what do endocrine glands secrete

A

hormones

- that work at distant parts of the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what do exocrine glands secrete

A

enzyme and lubricants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

name three endocrine glands

A

1) Pituitary gland
2) Thyroid gland
3) Parathyroid gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

where is the pituitary gland found

A

the hypothalamus (beneath the thalamus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what does the anterior pituitary gland produce

A

hormones that regulate most of the glands of the endocrine system

e.g. ACTH
LH
FSH
TSH
Prolactin
Somatorophin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

prolactin

A

stimulates milk production in mothers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

somatorophin

A

regulates growth of the body and tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what does the posterior pituitary gland produce

A
  • vasopressin (ADH)

- Oxytocin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

vasopressin (ADH)

A

prevents water loss from the kidney

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Oxytocin

A

that signals for delivery in pregnant women at the end of gestation and ejection of milk during breast feeding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

thyroid gland produces

A

thyroid hormone- T3 and T4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

T3 and T4

A

control metabolism, calcitonin (calcium homeostasis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

parathyroid produces

A

produced parathyroid hormones, calcium homeostasis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

example of exocrine cells

A
  • salivary gland
  • pancreas gland
  • mammary gland
  • sweat glands
  • sebaceous gland
  • lachrymal gland
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

generation of gland- in utero development

A
  1. Growth signal received (FGF family member)
  2. Proliferation of [daughter] cells occurs and extracellular protein degradation of enzymes produced
  3. Epithelial cells invade space created
    a. Exocrine glands
    i. Central part dies off to produce duct (canalicularisation)
    b. Endocrine glands
    i. Produce angiogenic factors to stimulate blood vessel growth in and around the epithelial cells
    ii. Link to [mother] cells broken through apoptosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

in thyroid follicles (endocrine) production of colloid between epithelial cells causes

A

expansion of follicle into a sphere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

endocrine glands are surrounded by

A

capillaries- quick transport fo hormones into the blood and to distant tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

hormone release in endocrine cells

A

directly released from cells e.g. B cells- insulin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

release of enzymes and lubricants from exocrine cells

A

secretory cells form an acids (circle shape)- all cells secrete into the acinus and the product from many cells gets released from a single duct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

two types of cells in exocrine glands

A

epithelial

  • cells lining the duct
  • cells that make secretly products
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

some cells at the end of the ducts change morphology and class by turning into

A

myoepithelial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

myoepithelial cells

A

have features of both epithelial and smooth muscle cells

- help eject sections from the duct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

types of duct structure

A

tubular

alveolar

compound

simple

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

simple

A

duct does not branch e.g. intestinal glands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

compound

A

duct branches

32
Q

tubular

A

tube shaped

33
Q

alveolar

A

rounder

34
Q

salivary glands structure

A

compound tubuloalveolar

  • ## branched
35
Q

exocrine glands have two types of secretions

A

mucous

serous

36
Q

development of the breast tissue starts

A

in utero

- development then stops until puberty

37
Q

At puberty what restarts breast development

A

oestrogen and progesteron

38
Q

what stimulates the production of milk in pregnancy

A

prolactin (colostrum and milk)

39
Q

oestrogen stimulates

A

formation of terminal end bulbs in prepuberty

40
Q

oestrogen and progesterone in puberty

A

ductal elongation

41
Q

progesteron

A

ductal elongation and side pranchion

42
Q

secreting cells can also be based on

A

how cells secrete product

43
Q

types of secretion

A
  • merocrine
  • apocrine
  • holocrine
  • cytocrine
44
Q

merocrine secretion

A

cells secrete substances by exocytosis- fusion of vesical with apical membrane
- e.g. acinar (alveolar) and endocrine glands of pancreas

45
Q

regulated secretion

A
  • Secretory granules accumulate in large vesicles and are released by exocytosis upon stimulation
    o Needs Calcium ions to work
46
Q

constitutive secretion

A
  • Secretory product is not concentrated into granules but packaged in small vesicles and continuously released to the cell surface
    o Used to repopulate the plasma membrane with plasma proteins
47
Q

apocrine

A

portion of the cell membrane and cytoplasm that contains excretion buds off
- e.g. lactating mammary gland, sweat glands in the axilla and externa genitalia

48
Q

holocrine

A

entire cell disintegrates to excrete its substance

- e.g. sebaceous glands of the skin and nose and tarsal glands in eyelid

49
Q

cytocrine

A

cells are released as recreations e

50
Q

example of cytocrine

A

spermatids in the seminiferous tubule

51
Q

regulated merocrine secretion

A
  • Uses ATP
    1) Content of vesicle can be anything in the cell
    2) Active secretion requires Ca2+ ions
    3) Vesicle migrates to cell surface along microtubules
    4) In presence of Ca2+ ions, membrane of vesicle fuses with plasma lemma
    5) Cargo release into extracellular space
52
Q

example of regulated merocrine secretion

A

Example: Insulin release
- Dependent on calcium influx for insulin to be secreted - is dependent on membrane depolarisation which allows for calcium channels to open to allow calcium to enter the cell

53
Q

holocrine secretion example

A

Sebaceous gland

  1. Secretory cell gradually fills up with secretory granules
  2. Cell organelles degenerate
  3. Cells die
  4. Plasma membrane breaks and the contents (secretum) empties
  5. Dead cells are replaced by mitotic division of the basal cells
54
Q

definition of glycosylation of proteins

A

The covalent attachment of sugars by enzymes to p[routines and lipids to form glycoproteins and glycolipids

55
Q

glycosylation occurs in the

A

golgi

56
Q

role of glycosylation

A
  • Avoid protein folding
  • Prevent protein digestion by intracellular proteases
  • Prevent lipid digestion by intracellular lipases
  • Cell recognition (blood groups)
57
Q

how many proteins undergo glycosylation

A

50%

58
Q

how many disorders of glycosylation are known

A

40- rare and lethal

59
Q

role of the golgi apparatus

A

1) Protein-containing vesicles from the ER transfer substances to the cis region of the Golgi apparatus
2) Golgi chemically modifies the proteins in its lumen e.g. by glycosylation
3) And targets them to the correct address

60
Q

types of transport in and out of the cell (4)

A

exocytosis
endocytosis
phagocytosis
pinocytosis

61
Q

exocytosis

A

• Secretion of molecules outside the cell via vesicle fusing to a membrane

62
Q

endocytosis

A

• Engulfing of molecules inside the cell via vesicle formation

63
Q

phagocytosis

A
  • Process by which cells envelop or engulf other cells or particles
  • Cells of the immune system: phagocytes (macrophages, dendritic, neutrophils, basophils, eosinophils)
64
Q

pinocytosis

A
  • Process by which liquid droplets are ingested by cells

* Used by all cells esp SMC

65
Q

transcytosis

A

movement across a membrane

66
Q

types of transpeitheilal transport

A

paracellular
transcellular
Carrier protein
cell surge recpetors

67
Q

paracellular

A

Molecules may move through aqueous channels in the intercellular junction (paracellular transport)
a. Amino acid for hormone production

68
Q

transcellular

A

Through lipid membranes (transcellular)

a. Steroid hormones (oestrogen, progesterone etc)

69
Q

carrier protein

A

Transported by carrier proteins into or out of the cell

70
Q

Molecules that are impermeable may bind to

A

cell surface receptors, be engulfed by the cell membrane (endocytosis) and then released inside the cell or expelled via exocytosis
a. Cholesterol transport (many drugs)

71
Q

3 types of glandular control

A

humoral
neural
hormonal

72
Q

humoral

A

exocrine and endocrine

e.g. substances in the blood may trigger release of hormone e.g. calcium

73
Q

neural

A

only exocrine

e.g. neurones stimulating hormone secretion

74
Q

hormonal

A

exocrine and endocrine

.g. the secretion of one hormone provides positive or negative feedback for the release of another hormone

75
Q

example of gland that has neural communication

A

hypothalamus to the pituitary

76
Q

Hypothalmo-hypophyseal portal system

A
  • Neurons in the hypothalamus synthesising trophic hormone release them into the capillaries of the portal system
  • The portal vessel carry the trophic hormones ( TSH) directly to the anterior pituitary
  • Endocrine cells release their hormones into the second set of capillaries for distribution to the rest of the body e.g. T3/T4- thyroxine
    o Provides negative feedback to Hypothalamus