physiology

Question 1

what are keratinocytes?

Answer 1

• produces keratin
• that protects the skin from abrasion/damage/heat

Question 2

what are melanocytes?

Answer 2

• produce melanin
• protects from UV rays

Question 3

what are Langerhern cells?

Answer 3

• produced in red bone marrow
• facilitate an immune response

Question 4

what are Merkel cells?

Answer 4

transmits sensory information to nerves in deeper layers

Question 5

what are phagocytes?

Answer 5

• neutrophils & macrophages
• emigrate to affected areas
• ingest foreign or dead tissues

Question 6

what is the effect of age on the skin?

Answer 6

• prolonged inflammatory phase of healing
• due to more protein degradation
• prolonged overall healing

Question 7

what are the 6 functions of the skin?

Answer 7

1 - thermoregulation
2 - blood reservation
3 - protection
4 - cutaneous sensations
5 - excretion and absorption
6 - synthesis of vitamin D

Question 8

what are the 5 cardinal signs of inflammation? PRISH

Answer 8

P - pain (chem release)
R - redness (inc BF)
I - immobility
S - swelling (fluid accum from plasma)
H - heat (higher BF)

Question 9

what happens in the inflammatory phase of wound healing?

Answer 9

• platelets cause haematoma
• bradykinin and histamine cause vasodilation and increased vessel permeability
• phagocytes remove foreign or dead tissue
• mesenchymal cells arrive

Question 10

what happens in the migratory phase of wound healing?

Answer 10

• scab forms
• epithelial cells grow underneath from stratum basale
• fibroblasts migrate to the wound and form scar tissue (glycoproteins and collagen)
• blood vessels begin to regrow

Question 11

what happens in the proliferative phase of wound healing?

Answer 11

• epithelial tissue continues to grow
• fibroblasts deposit collagen fibres in random patterns
• wound begins to contract
• 2-3 weeks

Question 12

what happens in the maturation phase of wound healing?

Answer 12

• remodelling of collagen fibres
• decreased fibroblasts
• blood vessels healed fully
• scab sloughs off once the epidermis is thick enough

Question 13

what are the 3 skin layers? EDS

Answer 13

epidermis
dermis
subcutaneous layer

Question 14

what is the epidermis?

Answer 14

• 5 layers (stratum)
  1 - stratum basale
  
  • deepest new skin cells made from stem cells
  • moves through the layers
    2 - stratum spinosum
  • cells joined tightly together
  • strength and flexibility
    3 - stratum granulosum
  • the border between live and dead cells
  • waterproof
    4 - stratum lucidum
  • layers of dead cells that act as protection
    5 - stratum corneum
  • 25-30 layers of flattened dead keratinocytes

Question 15

what is the dermis?

Answer 15

• made of elastin
• contains blood vessels
• subcutaneous glands = secret sebum to keep skin supple
• sweat glands = regulate temp and excrete waste

Question 16

what is the subcutaneous layer?

Answer 16

• lipid cells provide protection
• contains blood vessels and nerves

Question 17

what are the 3 phases of muscle strain healing?

Answer 17

inflammation
regeneration
remodelling

Question 18

what happens in the inflammation phase of muscle healing?

Answer 18

• necrosis of myofibrils
• vasodilation
• increased BV permeability
• phagocytosis
• haematoma formation

Question 19

what happens in the regeneration phase of muscle healing?

Answer 19

• stem cells migrate to the area and differentiate into myoblasts
• myoblasts develop into myotubes
  leading to myofibril regen
• fibroblasts produce collagen to stabilise wound and provide scaffolding for new muscle fibres

Question 20

what happens in the remodelling phase of muscle healing?

Answer 20

• maturation of regenerated myofibrils
• gradual recovery of muscle function
• reorganisation of scar tissue

Question 21

what are the different types of muscle contraction?

Answer 21

either isotonic or isometric
isometric = no change in muscle length
isotonic = change in muscle length

isotonic can either be concentric or eccentric

concentric = muscle shortens
eccentric = muscle lengthens

Question 22

what is the epimysium?

Answer 22

• outer layer
• dense
• irregular

Question 23

what is a fasicle and what surrounds it ?

Answer 23

• bundle of muscle fibres
• surrounded by perimysium

Question 24

what are muscle fibres and what surrounds them ?

Answer 24

• muscle fibres are made up of myofibrils
• and are surrounded by endomysium

Question 25

what do myofibrils contain?

Answer 25

• contractile sarcomeres
• sarcomeres are overlapping protein fibres called actin and myosin

Question 26

what does the golgi tendon do?

Answer 26

monitors the force of muscle contraction

Question 27

what is a muscle spindle?

Answer 27

monitors changes in muscle length

Question 28

what is the periosteum?

Answer 28

• outer layer
• protects and nourishes as it has a good blood supply

Question 29

what is the medullary cavity ?

Answer 29

• space inside bone
• lined by endosteum
• spaced and filled with yellow bone marrow
• hollowness means bones are light

Question 30

what is hyaline cartilage?

Answer 30

• shock absorbtion
• reduces friction between bones

Question 31

compact bone

Answer 31

• densly packed osteocytes
• protects and supports

Question 32

spongey bone

Answer 32

• made of lamellae arranged into trabeculae beams
• cavities are filled of red bone marrow
• RBM makes RBC
• cavities make bone lighter

Question 33

what is the epiphyseal plate?

Answer 33

growth plates in children
epiphyseal line in adults

Question 34

what is the diaphysis of a bone?

Answer 34

the main body of the bone

Question 35

what are the epiphyses of a bone?

Answer 35

the ends of the bone

Question 36

what are the 4 types of bone fractures

Answer 36

Open = bone out
Comminuted = crumbled
Greenstick = one side broken other bent only in children
stress = microscopic fissures