Connective Tissue Flashcards Preview

ESA1 - Body Logistics > Connective Tissue > Flashcards

Flashcards in Connective Tissue Deck (65)
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1
Q

What are the four basic tissue types?

A

Epithelial, Muscle, Nerve and Connective

2
Q

What are the 6 types of specialised connective tissues?

A

Adipose, Lymphatic, Blood, Haemopoietic, Bone and Cartilage

3
Q

What are the functions of connective tissue?

A
  • Connection (connects cells to form tissues, tissues to form organs etc)
  • Transportation (provides a medium for diffusion)
  • Protection (provides cushion between tissues and organs and provides insulation)
  • Storage (adipose tissue)
  • Defence (blood, lymph, fixed and wandering cells)
  • Wound healing (macrophages, fibroblasts, myofibroblasts)
4
Q

What is Connective Tissue Proper?

A

Connective tissue proper consists of both loose and dense connective tissue, fibres and ground substance

5
Q

What are the 3 fibres in connective tissue?

A

Collagen, Reticular and Elastin

6
Q

What is the importance of the 3 fibres found in connective tissue?

A

Collagen - Flexible with high tensile strength
Reticular - Provide a supporting framework/sponge
Elastin - Allows tissues to recoil after stretching

7
Q

What is ground substance?

A

Ground substance is a viscous, clear substance with a slippery feel. It has a high water content and is composed of proteoglycans

8
Q

What is a proteoglycan?

A

A proteoglycan is a large macromolecule that consists of a core protein to which glycosaminoglycans are covalently bound.

9
Q

What are glycosaminoglycans?

A

Glycosaminoglycans are long-chained polysaccharides. They attract water to form a hydrated gel that permits rapid diffusion but also resists compression.

10
Q

How are glycosaminoglycans bonded to proteoglycans?

A

By covalent bonds

11
Q

Name an example of a glycosaminoglycan.

A

Hyaluronic acid (present in ground substance of cartilage)

12
Q

What is the extracellular matrix?

A

This is a term used to describe a complex extracellular structural network consisting of ground substance and fibres.

13
Q

What are the features of loose connective tissue?

A
  • Many cells
  • Sparse collagen fibres
  • Abundant ground substance
  • Viscous, gel-like consistency
  • Important role in transport (by diffusion)
14
Q

What are the features of dense connective tissue?

A
  • Few cells, mainly fibroblasts
  • Many collagen fibres
  • Not much ground substance
15
Q

What is a fibroblast?

A

This is a cell in connective tissue which produces collagen and other fibres.

16
Q

Where is loose connective tissue usually found?

A
  • Found beneath epithelia (to facilitate diffusion)
  • Associated with epithelium of glands
  • Located around small blood vessels

All of the above are sites in which pathogens that have breached an epithelial surface can be destroyed by the cells of the immune system. Therefore, during these reactions, loose connective tissue can undergo swelling.

17
Q

What are the two types of dense connective tissue?

A

Regular and Irregular

18
Q

What are the features of regular dense connective tissue?

A

Collagen fibres are arrange in parallel bundles and are densely packed - fibroblasts are found between bundles.

These are designed to withstand stress in a single direction and so are seen in tendons, ligaments and aponeuroses

19
Q

What are the features of irregular dense connective tissue?

A

Collagen fibres are arranged in bundles orientated in various directions - fibroblasts are found between the bundles.

They are designed to withstand stress in multiple directions so are found in places like the submucosa of intestine and deep layers of the dermis.

20
Q

What is a ligament?

A

A ligament is a short band of tough, flexible, fibrous connective tissue that connects bone to bone.

21
Q

What is a tendon?

A

A tendon is a flexible band of strong fibrous connective tissue that connects muscle to bone.

22
Q

What is an aponeurosis?

A

This is a flat sheet of regular connective tissue with bundles of fibres in one layer often arrange at 90 degree angle to those in adjacent layers.

23
Q

What type of connective tissue is the dermis?

A

Dense irregular connective tissue

24
Q

What main two types of cells are found in connective tissue?

A

Fixed cells and wandering cells

25
Q

What are some examples of fixed cells found in connective tissue?

A
  • Fibroblasts (and myofibroblasts)
  • Melanocytes
  • Macrophages
  • Adipocytes
  • Mesenchymal ‘stem cells’
26
Q

What are some examples of wandering immune cells in connective tissue?

A
  • Leucocytes
  • Plasma cells
  • Monocytes
  • Eosinophils
  • Basophils
27
Q

What do fibroblasts synthesise?

A

Fibroblasts synthesise and secrete both ground substance and the fibres that lie within the ground substance

28
Q

What are myofibroblasts?

A

Myofibroblasts are modified fibroblasts that contain actin

29
Q

What are the cells primarily responsible for the formation of scar tissue?

A

Fibroblasts and myofibroblasts

30
Q

What are contained in the granules present in the cytoplasm of mast cells?

A
  • Histamine (increases blood vessel wall permeability)
  • Heparin (an anticoagulant)
  • Substances that attract eosinophils and neutrophils
31
Q

What is another name for reticulin?

A

Type III Collagen. Fibrilsform fibres around muscle and nerve cells and within lymphatic tissues and organs.

32
Q

What is the molecular structure of type I collagen?

A

Each molecule is composed of a triple helix of alpha chains.

33
Q

How are collagen fibrils produced?

A

Fibroblasts secrete procollagen that is converted to collagen molecules outside the cell. The collagen molecules are then aggregated to form the final collagen fibrils.

34
Q

What is required for the intracellular production of procollagen?

A

Vitamin C is required. Vitamin C deficiency leads to scurvy which involves poor wound healing and impaired bone formation.

35
Q

What occurs when you have abnormal type I collagen?

A

Osteogenesis imperfecta

36
Q

What do reticular fibres consist of?

A

Type III Collagen

37
Q

What is the primary component of elastic fibres?

A

Elastin - it itself enfolds and is surrounded by microfibrils called fibrillin

38
Q

Where are elastic fibres common?

A

Dermis, artery walls, lungs and sites bearing elastic cartilage

39
Q

What is the disorder caused by abnormal elastic tissue?

A

Marfan’s Syndrome - expression of the fibrillin gene is abnormal so elastic tissue is abnormal. Sufferers are abnormally tall, have frequent joint dislocation and can be at risk of aortic rupture.

40
Q

What are the two types of fat cells?

A

White and Brown

41
Q

Which type of fat is the majority of adipose tissue?

A

White

42
Q

Describe white fat cells

A

Unilocular adipose cells are almost completely filled by a single fat droplet. The cytoplasm is displaced to the rim of the cell and the nucleus to one side.

43
Q

Describe brown fat cells

A

Multilocular adipose cells contain any lipid droplets and a central nucleus. The brown colour is due to rich vascular supply and abundant mitochondria.

44
Q

What is ghrelin?

A

Ghrelin is ‘the appetite stimulator’. It is released from the stomach and, when elevated, sends a signal to your brain letting you know you’re hungry!

45
Q

What is leptin?

A

Leptin is ‘the appetite suppressor’. It is stored and secreted by fat cells and is released when you eat a meal, sending a signal to your brain to let you know you’re full!

46
Q

Where can dense regular CT found?

A

Tendons and ligaments

47
Q

Where can dense irregular CT be found?

A

Dermis of skin

48
Q

Where can elastic CT be found?

A

Between vertebrae of spinal column

49
Q

What are the main cells found in dense CT?

A

Fibroblasts

50
Q

What are the three types of loose CT?

A

Areolar, adipose, reticular

51
Q

What are fascia?

A

Coverings that help to support and compartmentalise

52
Q

What is osteogenesis imperfecta caused by?

A

Abnormal type I collagen

53
Q

What does osteogenesis imperfecta result in?

A

Bones that break easily

54
Q

List some symptoms of osteogenesis imperfecta

A

Bone deformities, recurrent fractures, blue sclera, short height, loose joints, bowed limbs, weak teeth, hearing loss, curved spine

55
Q

In osteogenesis imperfecta, why are the sclera often blue?

A

Due to the underlying choroidal veins which show through - due to the sclera being thinner because of the defective Type I collagen not forming correctly

56
Q

How does the deficiency/abnormality of type I collagen in osteogenesis imperfecta arise?

A

Amino acid substitution of glycine to bulkier amino acids in the collagen triple helix structure

57
Q

How is OI inherited?

A

Autosomal dominant

58
Q

List some symptoms of scurvy

A

Tiredness, muscle/joint pain, abnormal bleeding from gums etc, impaired wound healing

59
Q

Why does a lack of vitamin C cause scurvy?

A

Vitamin C needed as a cofactor to prolyl hydroxylase and lysyl hydroxylase which are the enzymes responsible for the hydroxylation of proline and lysine

60
Q

What is Marfan syndrome caused by?

A

Abnormal production of fibrillin - abnormal elastic CT

61
Q

List some characteristics of patients with Marfan syndrome

A

Tall, abnormally long fingers, long limbs, heart defects and lens dislocation

62
Q

What are sufferers of Marfan syndrome at risk of?

A

Aortic rupture

63
Q

How is Marfan syndrome inherited?

A

Autosomal dominant

64
Q

List some characteristics of ehlers-danlos syndrome

A

Stretchy skin, fragile skin, joint hyper mobility, bruise easily

65
Q

Why are people with syndromes such as Marfan and EDS at risk of aortic aneurysm?

A

Aortic walls are weak and the aorta is under high pressure so there is an increased risk of aneurysm or rupture