Session 5: Exocrine glands & connective tissue

Question 1

What is osteogenesis imperfecta?

Answer 1

• An inherited genetic brittle bone disease. It is autosomal dominant.
• Mutated collagen fibres do not knit together or not enough produced or both

Question 2

What are the 7 signs and symptoms of osteogenesis imperfect?

Answer 2

• Weakened bone (fractures are common)
• Short stature
• Presence of blue sclera
• Hearing loss
• Hypermobility due to loose joints
• Flat or arched feet
• Poor teeth development

Question 3

What is scurvy?

Answer 3

Vitamin C deficiency leads to synthesis of abnormal collagen that lacks usual strength
Associated with inability to heal wounds & bone fractures

Question 4

What are the 6 signs and symptoms of Scurvy?

Answer 4

• Gum disease & tooth loss
• Bruising of skin & hair loss
• Bleeding
• Poor wound healing
• Weakness & fatigue
• Impaired bone development in young

Question 5

What is Marfan’s syndrome?

Answer 5

Autosomal dominant disorder in which expression of fibrillin 1 gene is affected such that elastic tissue is abnormal.

Question 6

What are the 4 signs and symptoms of Marfan’s syndrome?

Answer 6

• Abnormally tall patients
• Arachnodactyly - abnormally long arms, legs & fingers
• Frequent joint dislocation
• Risk of aortic rupture

Question 7

Describe loose connective tissue.

Answer 7

• Contains many cells
• Few collagen fibres
• Much ground substance
• Viscous consistency

Question 8

Describe dense connective tissue.

Answer 8

• Contains few cells, almost all are fibroblasts
• Many collagen fibres
• Little ground substance

Split into regular & irregular

Question 9

Describe regular & irregular dense connective tissue.

Answer 9

• Regular = collagen fibres are arranged in parallel bundles & densely packed. Fibroblasts between fibroblasts - withstand stress in a single direction. Seen in tendons, ligaments & aponeuroses.
• Irregular = collagen fibres are arranged in bundles orientated in various directions - withstand stress in multiple directions. Seen in submucosa of intestines & reticular layer of dermis

Question 10

What are the 8 functions of the liver?

Answer 10

• Storage of metals & lipid soluble vitamins & sugars
• Anabolism of more than 60% of boy’s proteins eg plasma proteins
• Amino acid synthesis
• Haemopoiesis in embryo/foetus from week 5 to week 32
• Catabolism of drugs, hormones, haemoglobin, toxins, sugars & damaged RBCs after splenectomy
• Bile production
• Filtering cell debris from the blood
• Modifies hormones for excretion or function

Question 11

What are myoepithelial cells made of? What is their function?

Answer 11

Myosin and actin.
They contract and squeeze the contents of a mucous cell into ductile system through lumen

Question 12

What are fibroblasts?

Answer 12

Cells that synthesise the ECM, collagen & ground substance, producing the structural framework of connective tissue.

Question 13

What are mast cells?

Answer 13

Granulocyte-containing immune cells.

Question 14

What does brown adipose tissue do?

Answer 14

provides insulation & energy reserve, in neonates = generation of heat

Question 15

What does adipose tissue do?

Answer 15

= padding & shock absorber, insulation & energy reserve

Question 16

What is ground substance?

Answer 16

A viscous, slippery substance with a water content composed primarily of proteoglycans =

Question 17

What are proteoglycans?

Answer 17

Large macromolecule consisting of a core protein with glycosaminoglycans (GAGs) attached. GAGs attract water to form a gel that permits diffusion but resists compression.

Question 18

How do GAGs resists compression

Answer 18

GAGs attract water to form a gel that permits diffusion but resists compression.

Question 19

What is hyaluronic acid?

Answer 19

A type of glycosaminoglycan (GAG) that binds to the proteoglycan core protein to form huge hydrophilic macromolecules which resist compression without inhibiting flexibility.
Main GAG in cartilage.

Question 20

What is the importance of Vitamin C?

Answer 20

Required for the intracellular production of procollagen which is converted to collagen molecules outside of the cell and aggregate to form the final collagen fibres.

Question 21

What is the structure of Type 1 collagen?

Answer 21

Triple helix of alpha chains

Question 22

What do elastin fibres do?

Answer 22

Allow tissue to recoil after stretch or distension.

Question 23

What are macrophages?

Answer 23

Phagocytic antigen presenting cells

Question 24

What are 6 functions of connective tissue?

Answer 24

• Wound healing
• Defence against infection
• Storage reserve fuels and cells
• Protection - provides a cushion between tissue
• Transportation - medium for the diffusion
• Binding and supporting eg holding skin, organs and tissue together

Question 25

What are reticular fibres? What do they do?

Answer 25

Type of fibre composed of type 3 collagen secreted by reticular cells.
They can cross-link to form reticulin which provides a supportive framework for soft tissue eg liver and bone marrow

Question 26

What are the types of cells found in the liver?

Answer 26

Kupffer cells, stellate (ito) cells and hepatocytes

Question 27

What are kupffer cells? What are 2 of their functions?

Answer 27

Specialised macrophages that make up the sinusoidal lining
Functions:
- trap and phagocytose any damaged/aged erythrocytes that were missed by the spleen
- after splenectomy, take over removal of 120 day old erythrocytes

Question 28

What are stellate (ito) cells? What do they do?

Answer 28

Cells full of vacuoles containing Vitamin A in the cytoplasm
Functions:
- in liver cirrhosis they lose their vitamin A storage capability and differentiate into myofibroblasts
- synthesis and deposit collagen within the perisinusoidal space resulting in liver fibrosis

Question 29

What is the function of bile?

Answer 29

Emulsify fats and assists in vitamin K absorption from small intestine

Question 30

How does the hepatic blood supply work?

Answer 30

It connects the SI and liver.
- Nutrients from the stomach and SI are absorbed in the first capillary bed then hepatocytes detoxify nutrients of toxins in liver

Question 31

What type of gland is the submandibular gland?

Answer 31

Mixed gland -> serous, mucous and mixed acini which secretes thick mucus and thin enzyme contained in saliva
- Compound tubuloacinar

Question 32

What is the function of striated ducts?

Answer 32

Prevent water loss

Question 33

What type of gland is the parotid gland?

Answer 33

Acinar, serous exocrine
Contains acini and striated ducts

Question 34

What occurs in mumps?

Answer 34

Viral infection causing swelling of side of head due to blockage of striated duct cause fluid accumulation (parotid gland)

Question 35

Which cells secrete mucus?

Answer 35

Goblet cells - they produce mucin and secrete them onto epithelial surface where they dorm mucus.

Question 36

Where are mucus cells found?

Answer 36

Jejenum, line ducts of simple tubular glands in the large intestine and respiratory tract
They support the removal of foreign particles

Question 37

What is the importance of mucus?

Answer 37

Lubricates, protective barrier, aids the movement of foreign particles & substances along epithelial cell surfaces.

Question 38

Describe serous glands.

Answer 38

• Produce thin, watery secretion containing proteins, antibodies & zygomens.
• Contain large striated ducts
• Cell contain round, central nuclei
• Stain dark due to the presence of zygomens

Question 39

Describe mucous glands.

Answer 39

-Produce thick, viscous secretions containing mucin
- Contain small, striated ducts
- cells contain flattened nuclei against basement membrane
- Stain light due to mucin.