Glandular Tissues and Cell Secretion Flashcards Preview

Z OLD Tissues of the Body > Glandular Tissues and Cell Secretion > Flashcards

Flashcards in Glandular Tissues and Cell Secretion Deck (136):
1

What is a gland?

An epithelial cell or collection of cell specialised for secretion

2

How can glands be classified?

- Destination 
- Structure 
- Nature
- Method

3

What can glands be classified into based on destination?

#NAME?

4

What do exocrine glands have?

Ducts

5

Where do exocrine glands secrete?

Onto epithelial surfaces

6

What do endocrine glands produce?

Hormones

7

Where do endocrine glands secrete?

Into the bloodstream

8

What can glands be classified into base on structure?

#NAME?

9

What are the possible differences between the secretory part of a gland?

- Is it unicellular or multicellular?
- It it acinar (alveolar) or tubular? 
- Is it coiled or branched?

10

What are the different types of duct systems?

- Simple gland 
- Compound gland

11

What is meant by a simple gland?

Single duct

12

What is meant by a compound gland?

Branched ducts

13

How to ducts branch?

From main duct →  interlobular →  intralobular →  intercalated

14

What do ducts define?

The structure of complex glands

15

What kind of gland is a goblet cell?

Unicellular exocrine

16

Where are goblet cells found?

In pseudostratified epithelium of respiratory system

17

Where is the ion channel molecule CFTR normally found?

The apical membrane

18

In what condition is the CFTR protein not present?

Cystic Fibrosis

19

Why is the CFTR protein not present in CF?

The mutant protein is normally destroyed before it reaches the apical membrane

20

What is the result of the absent CFTR gene?

Cl - transport across membrane seriously compromised

21

What is the result to mucous of the compromisation of Cl -  transport across the membrane?

It becomes viscous

22

Why does faulty Cl -  transport lead to viscous mucous?

The lack of Cl - , and therefore Na +  (as sodium usually follows Cl - ), changes the osmotic potential, which means that water doesn’t leave the epithelium in sufficient quantities, so the mucus is not adequately hydrated, thus becoming viscous

23

What problems does viscous mucus cause?

- Serious pulmonary infection 
- Meconium ileus 
- Constipation
- Invagination of parts of GI tract

24

How does viscous mucus result in serious pulmonary infection?

Because the mucus can’t be as readily moved to oropharynx for swallowing

25

What is meconium ileus?

Inability to pass first faeces

26

What causes the GI symptoms of CF?

Viscous mucus of the GI tract

27

What happens to pancreatic ducts as they merge towards epithelium?

They become bigger

28

When are multicellular glands considered simple?

If the ducts do not branch

29

Give the 4 types of simple glands

- Simple tubular 
- Simple coiled tubular
- Simple branched tubular
- Simple acinar

30

When are multicellular glands compound?

If the ducts branch

31

Give the 3 types of compound glands

#NAME?

32

What is a compound tubuloalveolar gland?

A mixture of tubular and alveolar

33

What can glands be classified into by nature of secretion?

- Mucous 
- Serous

34

What do mucous glands produce?

Secretions that contain mucins

35

What are mucins?

Highly glycosylated polypeptides

36

What happens to mucins with later?

They swell a lot

37

How do mucous cells stain with H&E sections?

Poorly

38

What do serous membranes secrete?

#NAME?

39

How do serous cells stain in H&E sections?

Pink, as they are eosinophilic

40

What can glands by classified into based on method of secretion?

#NAME?

41

What kind of secretion do the vast majority glands use?

Merocrine

42

What is merocine secretion also known as?

Exocytosis

43

Describe the process of merocrine secretion

- Membrane bound component approaches cell surface
- Bounded membrane fuses with plasma membrane 
- Contents in continuity with extracellular space

44

What has happened to the plasma membrane following merocrine secretion?

It is transient larger

45

What must happen to the plasma membrane following merocrine secretion?

It must be retrived

46

Why must the plasma membrane be retrieved following merocrine secretion?

It stabilised the cell SA, otherwise the membrane would get very big

47

Describe the process of apocrine secretion

-  Non-membrane bound structure approaches the cell surface membrane 
- Makes contact and pushes up apical membrane, so a thin layer of cytoplasm drapes around the droplet
- Membrane surrounding droplet pinches off from the cell

48

Give an example of a type of molecule that may use apocrine secretion?

Lipid

49

What happens to the plasma membrane following apocrine secretion?

It is transiently smaller

50

What needs to be done following apocrine secretion?

Membrane needs to be added to regain the area

51

Give an example of where apocrine secretion occurs?

Mammary gland

52

What is secreted from the acini of the mammary gland?

Milk

53

What is needed to assist secretion in the mammary gland?

Myoepithelial cells

54

What kind of secretion to apocrine sweat glands use?

Merocrine

55

Why are apocrine sweat glands contradictorily named?

Because cytoplasmic blebbing not indicative of apocrine secretion

56

Where do apocrine sweat glands occur?

#NAME?

57

What kind of secretion do eccrine sweat glands use?

Merocrine

58

How do eccrine sweat glands work?

The myoepithelial cells contract, facilitating transport of luminal contents towards the duct

59

What can sweat testing for abnormally salty sweat confirm?

A CF diagnosis

60

Why do CF sufferers have abnormally salty sweat?

Because the absence of CFTR proteins in the apical membrane of epithelial cells lining the ducts of the sweat gland results in poor reabsorption of chloride ions, resulting in sweat rich in them

61

What kind of sweat does a heathy person secrete?

Hypotonic

62

Why do people normally secrete hypotonic sweat?

Don’t want to waste ions

63

Describe the process of holocrine secretion

#NAME?

64

Give an example of somewhere holocrine secretion occurs?

Sebacous gland

65

What does a sebaceous gland do?

Undergoes holocrine secretion to fill the hair follice with sebum

66

What is endocytosis?

Engulfing material initially outside the cell

67

Where are endo- and exocytosis coupled?

In trans-epithelial transport

68

Describe the process of trans-epithelial transport

#NAME?

69

What can happen to molecules too large to penetrate membranes?

They can be shunted from one component of the body to another by trans-epithelial transport

70

Do molecules in trans-epithelial transport cross membranes?

No

71

Describe the structure of the Golgi apparatus

- Stack of disk shaped cisternae 
- One side flattened, other concave
- Disks have swellings at edges

72

In what direction to substances move through the Golgi?

From the flat to concave surface

73

What happens to the swellings at the edge of the Golgi cisternae?

Distal swellings pinch off as migratory Golgi vacuoles

74

What is glycosylation?

Adding sugar to proteins

75

Where does glycosylation occur?

In the cisternae of the Golgi

76

What is the function of the Golgi?

- Sorting into different compartments 
- Packing through condensation of contents
- Glycosylation
- Transport of resultant vesicles

77

How does the Golgi sort into different components?

Puts them into different vacuoles

78

How do vesicles transport through the Golgi?

Move through the Golgi in 1 direction

79

Where are the products from the Golgi destined?

- Majority extruded in secretory vesicles 
- Some retained for use in cells 
- Some enters plasma membranes

80

What glands extrude products from the Golgi in secretory vesicles?

All those secreting substances like mucus onto epithelial surfaces

81

Give an example of where Golgi products are retained for use in cells?

Lysosomes

82

Give an example of where Golgi products enter the plasma membrane?

Glycocalyx

83

What is the advantage of glycosylation?

Branching sugars offer complex shapes, which allow for specific interactions in glycocalyx

84

How do glycosylated proteins interact with other proteins?

In a very specific way

85

Why does glycosylation have the potential for such specificity?

Because although there are only 6 to 8 sugar monomers, they can produce 1000’s of sugars if they’re put together in different combinations

86

What happens if the glycosylated layer is destroyed by enzymes?

It alters many specificity based properties of the cell

87

What properties of a cell might be altered by destruction of the glycosylated layer?

- Adhesion to substrates and neighbouring cells 
- Mobility 
- Communication with neighbouring cells 
- Contact inhibition of movement and division

88

How can secretion be controlled?

- Nervous 
- Endocrine
- Neuro-endocrine 
- Negative feedback of chemical mechanism

89

Give an example of nervous control of secretion

Sympathetic stimulation of adrenal medullary to release adrenaline

90

Give an example on endocrine control of secretion

ACTH stimulates the adrenal cortex to secrete hormones such as cortisol

91

Give an example of neuro-endocrine control of secretion

Nervous cells of hypothalamus controls ACTH secretion

92

Give an example of negative feedback on a chemical mechanism controlling secretion

Inhibitory effect of high thyroxine (T3 and T4) on TSH synthesis

93

Give 3 examples of exocrine glands

- Unicellular glands (goblet cells) 
- Parotoid glands
- Submandibular glands

94

Where are goblet cells found?

Jejenum and colon

95

Give 4 examples of endocrine glands

- Pancreas
- Thyroid gland
- Parathyroid glands 
- Adrenal (superarenal) glands

96

What are the 3 main salivary glands?

- Parotid 
- Submandibular 
- Sublingual

97

Are salivary glands mucus or serous?

Mixed

98

What are serous demilumes?

An artifactual crescent moon of serous tissue

99

What causes serous demilumes?

With conventional fixation, mucous cells swell, releasing mucus, which squeezes serous cells out to the edge

100

Is the pancreas exocrine or endocrine?

Both

101

Where is the head of the pancreas?

In the curl of the duodenim

102

What does the pancreas do?

- Churns out alkaline bicarbonate ions 
- Releases digestive enzymes 
- Produce insulin and glucagon

103

Why does the pancreas churn out bicarbonate ions?

To neutralise the acid released by the stomach

104

Why does the acid released by the stomach need to be neutralised?

Because the small intestine is not adapted to highly acidic conditions

105

Give 4 digestive enzymes released by the pancreas

#NAME?

106

What happens to the insulin and glucagon produced by the pancreas?

It’s secreted into the bloodstream

107

What is wrong with the secretions of the pancreas in cystic fibrosis?

They contain too little water, and so become thickened

108

What is the result of the thickened secretions of the pancreas?

The ducts become blocked

109

What is the result of blocked pancreatic ducts?

- Painfully inflamed pancreas (pancreatitis) 
- Pancreas becomes fibrotic 
- Gut receives insufficient pancreatic digestive enzymes, which results in malabsorption

110

What does malabsorption lead to?

Secretion of fat in faeces and diarrhoea

111

How does the rate of deterioration of the endocrine pancreas differ from that of the exocrine?

It’s slower

112

Why is the rate of deterioration of the endocrine pancreas slower?

Because it has no exocrine ducts

113

What are 3 cell types of pancreatic islets of Langerhans?

- Alpha 
- Beta
- Delta

114

What does each islet of Langerhan have?

An exocrine acinus

115

What does the thyroid gland consist of?

Simple cuboidal epithelium follices

116

Where is the thyroid gland found?

Wrapped around the trachea

117

What does each follicle have?

Homogenous colloid

118

What does the thyroid gland need to perform its function?

Good blood supply

119

Why does the thyroid gland need good blood supply?

Because it’s an exocrine gland, and so is secreting into the bloodstream

120

What happens to the lining cells of the thyroid gland when it’s active?

They become slightly columnar

121

What are the steps of thyroid hormone synthesis?

- Thyroglobulin is synthesised and secreted
- Uptake and concentration of iodine from blood 
- Iodine is oxidised, and released into colloid 
- Iodination of thyroglobulin in colloid 
- Formation of T3 and T4 hormones by oxidative coupling reactions 
- Resorption of colloid by receptor-mediated endocytosis
- Release of T3 and T4 from cell by exocytosis

122

What is the purpose of the thyroid gland?

It thyroxin in T3 and T4 states at correct level

123

What do parathyroid glands secrete?

Parathyroid hormone (PTH)

124

How many parathyroid glands are there?

Usually 2, sometimes 3, pairs

125

What does PTH control?

The level of calcium in the blood

126

What must be done in the case of a thyroidectomy?

The parathyroid glands must be left behind

127

Where are the adrenal glands found?

Sitting on top of each kidney

128

What does each adrenal gland consist of?

#NAME?

129

What does the adrenal medulla secrete?

Adrenaline and noradrenaline

130

What does the adrenal cortex produce?

Corticosteriod hormones

131

What does the adrenal cortex consist of?

3 layers, each producing different hormones

132

What are the 3 layers of the adrenal cortex?

- Zona glomerulosa 
- Zona fasciculata 
- Zona reticularis

133

Which zone of the adrenal cortex is the closest to the artery?

Zona glomerulosa

134

What does the zona glomerulosa produce?

Aldosterone

135

What does the zona fasciculata produce?

Primarily, cortisol

136

What does the zona reticularis produce?

Primarily, weak male hormone