BL2 Flashcards by Alex Wilton

What is a organ defined as?

Two types of tissue

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How are cells held together? 3

Tight junctions
Desmosomes
Gap junctions

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What do tight junctions do?

Form a seal

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Function of a desmosomes?

Strengthens

Stops stretching

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Function of a gap junction?

Communication

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How do cells anchor on the basement membrane? Give examples of where these are found?

Hemidesmosomes

Found in abrasive tissue such as skin epithelium of oral cavity

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What’s a focal adhesion?

Attaches cells to basement membrane using their intracellular actin filaments

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What’s the structure that the focal adhesion uses to bind to the basement membrane?

Integrins

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What’s in integrin?

2 functions

Transmembrane protein that attaches a cells cytoskeleton to the extra cellular matrix

Two main functions are:
Attachment
Signal transduction

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To get a tissue culture, how would you separate the cells?

Collagenases

Microdissection

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Name the 6 types of cell communication.

Direct contact (gap junctions
Autocrine
Paracrine
Endocrine
Synaptic communication
Neurocrine

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What are the four basic types of tissue?

Epithelial
Muscle
Nerve
Connective tissue

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Give four examples of specialised connective tissue?

Adipose
Lymphatic
Blood
Haemopoietic
Cartilage
Bone

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What is an epithelioid ?

Cells that don’t have a surface (epithelial)

Leydig cells in testes
Lutein in ovary
Islets of langerhans
Parenchyma of the adrenal gland

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Three specialisations of the apical domain in an epithelial cell?

Microvilli
Stereocilia (sensory hairs and epididymis)
Cilia

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Six functions of connective tissue?

1) Connects (duh)
2) Transportation (provides a medium for transportation)
3) Protection (cushions and sheaths)
4) storage
5) Defence
6) Wound healing

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What is connective tissue made up of? 3

Cells
Fibres
Ground substances

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Types of fibres in connective tissue. 3

Bonus points for function

Collagen - flexible high tensile strength
Elastin- allows stretch and recoil
Reticular - provide a supporting framework/sponge

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What’s the ground substance composed of in connective tissue?

Water
Proteoglycans (macromolecule consisting of a core protein to which glycosaminoglycans GAGs are covalently bonded)

A unique GAG is hyaluronic acid

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What is hyaluronic acid?

It’s a unique GAG. That binds the proteoglycans together to form a gigantic hydrophilic macromolecule

A GAG is a long chain polysaccharide that covelently binds to a core protein making a proteoglycan

Proteoglycans and water make up the ground substance in connective tissue

What’s makes up the extra cellular matrix?

Ground substance and fibres

What are the two types of connective tissue proper?

Loose
- many cells, spared collagen fibres, abundant ground substance, important role in transport

Dense

few cells (nearly all fibroblasts)
many collagen fibres
little ground substance

Where is loose connective tissue usually found?

Beneath epithelial tissue

Around small blood vessels

Associated with epithelium of glands

What can dense connective tissue be broken down into?

Describe the structures
Composition
Effect on stress
Where is it found

Regular
- parallel bundles of collagen fibres
- designed to withstand stress in a single direction
E.g. found in tendons ligaments and aponeuroses

Irregular

collagen fibres in different directions
designed to withstand stress from different directions
E.g. Submucosa of intestines and deep layer of demis

Tendons and ligaments are types of what connective tissue?

Dense regular connective tissue

What do ligaments connect?

Bone to bone

Cells of connective tissue. Fixed or free? | The different types?

Both Fixed - fibroblasts, melanocytes, mast cells, macrophages, adipocytes, mesenchymal stem cells Wandering cells Leucocytes, plasma cells, monocytes, eosinophils, basophils

What do fibroblasts produce?

Fibres and ground substance Myofibroblasts are modified fibroblasts that contain actin. Responsible for contraction in wound healing

What's a mast cell? Function Structure

Contains multiple granules - histamine - heparin - substances that attract eosinophils and neutrophils Secretion to substances to attract other cells/reactions

How many types of collagen are there? Type 1? %? Present in? Type 2? present in? Type 3? Know as?

28 Type one. 90%. Fibres arranged into fibres and bundles. Tendons, organ capsules, skin dermis Type 2. Fibrils not fibres. Hyaline and elastic cartilage Type 3. Form fibres round muscle, nerve and lymphatic tissues and organs. Known as reticulate

Collagens structure is ? How is it produced?

Triple helix of alpha chains Procollagen is produced inside the cell and assembled outside. Vitamin C is needed for production of procollagen - scurvy

What's Marfan syndrome? - > type of disease - > Pathophys - > Side effects

Autosomal dominant disorder Fibrillin gel is abnormal-> elastic tissue is abnormal. = more elastic tissue Sufferers are tall, joint dislocations , and risk of catastrophic aortic rupture(aneurysm)

What ghrelin do? Leptin?

Ghrelin = appetite stimulator. Age gender and blood glucose affect ghrelin and is used to stimulate hunger Leptin is stored and secreted by fat when you eat a meal. It tells the brain you are full

What are the three general types of CT?

1) CT proper (loose and dense) 2) Specialised CT (blood&Lymph) 3) Supporting CT (cartilage,bones, bone marrow)

CTs are made up of cells. Name 3 of the 5 cell types which are fixed.

1. Fibroblasts 2. Fixed macrophages 3. Mast Cells 4. Adipose cells 5. MELANOCYTES

What are the 3 types of fibres in CTs?

Reticular Collagen Elastic

What is senescence?

The process of age deterioration

What is apoptosis?

Programmed cell death

What is necrosis?

Un-planned cell death

Why do necrotic cells swell and burst?

Failure of the Na/K ATPase

What are the limits of pH?

6.8 to 7.8

What organs are usually effected first due to pH changes

lungs kidneys liver

What is shock?

Global cellular and tissue hypoxia/ reduced o2 delivery

If a compartment has a high osmolarity... what does that mean?

It has a high conc of SOLUTES and PROTEINS | just proteins is called oncotic pressure

What protein is the most abundant in the body? | HARD- where is it made?

Albumin Liver /\ in liver cirrhosis. Less albumin in blood -> fluid build up in interstitial space

Whats the difference between collagen fibres and reticular fibres?

Collagen - FLEXIBLE with high TENSILE STRENGTH | Reticular - SUPPORTING FRAMEWORK

How do you identify between loose and dense connective tissue? )break it down(

Loose - more cells, sparse collagen fibres, lots of ground substance Dense - few cells (fibroblasts), many collagen fibres, not much ground substance

What CT is an aponeurosis made up of?

Dense Regular CT

What is Fibrillin?

Componant that is needed to for elastin | Produced by fibroblasts