Body Logistics

Question 1

What are the 4 valves of the heart? What do they seperate?

Answer 1

Tricuspid valve - between the right atrium and the right ventricle
Pulmonary valve - between the right ventricle and the pulmonary artery
Mitral valve - between the left atrium and left ventricle
Aortic valve - between the left ventricle and the aortic arch

Question 2

What are the 3 layers of walls of arteries and veins? and their composition?

Answer 2

Inner = tunica intima ( endothelium and elastic lamina)
Middle = tunica media ( elastic lamina and connected by gap junctions)
Outer = tunica externa ( connective tissue, lymph vessels and nerve fibres)

Question 3

What are the 3 types of muscle

Answer 3

Smooth muscle
Cardiac muscle
Skeletal muscle

Question 4

Properties of Skeletal muscle

Answer 4

• long parallel cylinders
• multiple peripheral nuclei
• fasicle bundles
• striated

Question 5

Properties of Cardiac muscle

Answer 5

• striated
• centrally positioned nuclei
• intercalated discs
• branching
• T tubules on Z line
• junctions join cells end to end

Question 6

Properties of Smooth muscle

Answer 6

• spindle shaped cells with central nucleus
• not striated, no T tubules, no sarcomeres
• connective tissue, gap and desmosome junctions

Question 7

What are the 3 types of cartilage?

Answer 7

Hyaline cartilage
Fibrocartilage
Elastic cartilage

Question 8

What is hyaline cartilage?

Answer 8

• matrix of proteoglycans, hylauronic acid and type 2 collagen
• in articulating surfaces (rib cage, nose, trachea..)

Question 9

What is Fibrocartilage?

Answer 9

• chondrocytes and fibroblasts present
• dense regular CT and hyaline cartilage
• In intervertebral and articular discs and meniscus of knee

Question 10

What is Elastic cartilage?

Answer 10

• Elastic fibres in extracellular matrix
• in external ear and epiglottis
• dark stained on H&E

Question 11

Outline fracture repair

Answer 11

1. Haematoma forms - swelling occurs, bone cells at fracture die and are removed.
2. Fibrocartilagenous callus formation - procallus of granulation tissue forms, sleeve of hyaline cartilage forms, bone reconstructed to spongy bone
3. Bony callus formation - trabecular bone forms, callus converted to cancellous bone, endochondral and intramembraneous ossification = cancellous bone
4. Bone remodelling - cancellous bone remodelled to compact bone.

Question 12

What is osteoporosis? The different types and the risk factors?

Answer 12

• metabolic bone disease
• mineralised bone decreases in mass and can no longer provide mechanical support
• Type 1 = postmenopausal women - increased osteoclast number due to oestrogen withdrawal
• Type 2= elderly - attenuated osteoblast function
• risk factors - genetic, insufficient calcium intake, exercise and smoking