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LS1 Histology > Connective tissues and skin (rest look at Callum's ESA1 > Flashcards

Connective tissues and skin (rest look at Callum's ESA1 Flashcards

1
Q

What are some of the various functions of connective tissues?

A
  1. Structural - links together muscle, nerves and epithelium
  2. Metabolic support - medium for diffusion of nutrients and waste
  3. Physiological support - protection against infection and aid in injury repair
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2
Q

Name a liquid connective tissue with gas transport and immune defence functions

A

Blood

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3
Q

Name solid connective tissues with protective, mobility and structural functions

A

Cartilage and bone

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4
Q

What makes up the ground substance?

A

Hyaluronate proteoglycan aggregates

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5
Q

Where can a mucous connective tissue be found?

A

Umbilical cord

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6
Q

Name the three types of regular connective tissue

A
  1. Loose (areolar) connective tissue
  2. Dense connective tissue
    (i) regular
    (ii) irregular
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7
Q

List some specialised connective tissues

A 
Adipose tissue
Blood
Cartilage
Bone
Lymphatic tissue
Haemopoietic tissue
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8
Q

Mesenchyme (embryonic connective tissue) is pluripotent and differentiates into which rise to which connective tissue cells (as well as serous membranes, vascular and urogenital systems and to muscle)?

A

Chrondroblasts -> cartilage
Lipoblasts -> fat cells
Fibroblasts -> ligament, tendon, capsules, general supporting tissues
Osteoblasts -> bone
(Myoblasts -> skeletal muscle (not a connective tissue)

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9
Q

Mesenchymal cells in the adult that persist, have what function?

A

Can give rise to new connective tissue when healing is required

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10
Q

What shape are mesenchymal cells?

A

Spindle shaped

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11
Q

What makes up the structure of hyaluronate proteoglycan aggregates?

A

Linear aggregates of hyaluronic acid (itself a GAG) with attached proteoglcyan monomers (core protein to which ca100 GAG units attach

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12
Q

How do GAGs contribute to the hydration of the ground substance?

A

They have a high density of negative charge which attracts water, forming a hydrated gel

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13
Q

Where is type 1 collagen found?

A

Tendons, capsules of organs and skin dermis

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14
Q

Where is type 2 collagen (elastin) found?

A

Hyaline and elastic cartilage

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15
Q

Where is type 3 collagen (reticulin) found?

A

Around muscle and nerve cells and within lymphatic tissues and organs

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16
Q

Why does collagen type 1 fibril have periodic banding?

A

Because each fibril is composed of staggered collagen molecules

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17
Q

Describe the structure of type 1 collagen

A

Every third aa of the alpha-chain is glycine
Collagen molecule = Triple helix of alpha chains
Each fibril is composed of staggered collagen molecules

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18
Q

What banding pattern do type 1 collagen make?

A

68nm repeat

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19
Q

What do elastic fibres consist of?

A

Primarily elastin, which enfold and are surrounded by microfibrils of fibrillin

20
Q

What are the clinical signs of Marfan’s syndrome?

A

Abnormally tall
Exhibit arachnodactyly (long and slender fingers and toes)
Frequent joint dislocation
Risk of aortic rupture

21
Q

What is the inheritance pattern of Marfan’s syndrome?

A

Autosomal dominant disorder causing abnormal expression of the fibrillin gene

22
Q

In an artery what makes up the tunica intima?

A

Endothelial cells

23
Q

What type of collagen fibre makes up the tunica media of arteries?

A

Elastic fibres (type 2 collagen)

24
Q

What type of collagen fibre makes up the tunica adventitia of arteries?

A

Collagen (type 1)

25
Q

What type of cell produces the elastin, collagen and matrix in the tunica media?

A

Smooth muscle cells

26
Q

Why does dermis contain elastic fibres and irregularly orientated densely packed bundles of collagen?

A

Elastic fibres -> stretch and restore shape after bent/folded
Multiple orientation -> resist forces in multiple directions and therefore shearing

27
Q

What type of connective tissue makes up capsules of organs?

A

Varies from loose to dense connective tissue

28
Q

Describe the cell ultrastructure of a fibroblast

A

Abundant rER - synthesising and glycosylating proteins

Abundant secretory vesicles

29
Q

What do mast cells look like under the microscope?

A

Abundant granules which can obscure the nucleus when stained with basic dyes

30
Q

Where are mast cells found?

A

Connective tissue near blood vessels but NOT in the CNS (to avoid damaging effects of oedema there)

31
Q

What do mast cell granules contain?

A
  1. Heparin - anti-coagulant
  2. Histamine - increases blood vessel wall permeability
  3. Cytokines that attract eosinophils and neutrophils
32
Q

How are mast cells activated, releasing their granules?

A

When IgE molecules on their surface are cross-linked by binding to an allergen

33
Q

Name the two types of embryonic connective tissue

A

Mesenchyme and Mucous connective tissue

34
Q

What is the difference in the development of white and brown adipocytes?

A

Both are derived from mesencymal tissue which differentiates into early lipblasts, which develop numerous lipid droplets in their cytoplasm. In white adipose tissues these multiple droplets fuse into a single large droplet which displaces all other cell contents to the periphery. In brown adipose tissue these multiple lipid droplets remain separate and have a central nucleus

35
Q

In typical H&E stained, wax-embedded preparations of adipose tissue why do cells appear white and empty?

A

The toluene and xylene used for tissue preparation has dissolved away the lipid

36
Q

Where is brown adipose tissue found in the adult and newborn?

A

Newborn - sternum, scapula and axillae

Adult -chest and neck

37
Q

Why is brown adipose tissue brown?

A

Due to its rich vascular supply and abundant mitochondria. It has a high respiratory capacity for the generation of heat.

38
Q

What is a distinctive feature of neutrophils under the miscroscope?

A

One nucleus, but looks like 5. In females can have a stick poking out (inactivated X chromosome)

39
Q

What is a major underlying cause of skin ageing and wrinkling?

A

UV-induced injury to dermal collagen and elastin. This is called ‘solar elastosis’

40
Q

List two skin cancers

A

Malignant melanoma

Basal cell carcinoma - relatively benign if dealt with quickly but can eat away all the surface of your face

41
Q

Why does hair turn grey?

A

Some melanocytes stopping functioning in hair follicles (this does not happen in the epidermis)

42
Q

What is the cause of ‘port wine stain’ birth marks?

A

Congential malformation of dermal blood vessels -> increase in number of dermal capillaries and vasodilation

43
Q

What does the pilosebaceous unit contain?

A

hair follicles
sebaceous glands
smooth erectopilus muscle

44
Q

What are three causes of acne?

A
  1. Abnormal differentiation of sebaceous gland ducts
  2. Increased sebum production
  3. Infection with normally harmless skin bacteria
    These changes in SGs normally occur at puberty
45
Q

Where are sebaceous glands most abundant?

A

On the face. The typical site of acne

46
Q

What is hyperhidrosis?

A

Increased sweating the cause of which is normally unknown. May affect only the palms and soles

47
Q

What can disrupted skin barrier (e.g. in extensive psoriasis) lead to?

A 
Loss of fluid -> moist skin
Loss of protein
Loss of other nutrients
Loss of heat (vasodilation)
Excessive absorption of potentially harmful exogenous agents, especially drugs

LS1 Histology (13 decks)

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