Cartilage and bone physiology Smith Week 2 Flashcards

1
Q

what type of cells make up cartilage?

A

chondrocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

cartilage is structurally designed to do what 4 things?

A
  1. withstand tension and compression
  2. provide low friction surface at joints
  3. provide support to soft tissue
  4. provide a framework for long osteogenesis during development
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

how is cartilage different from bone?

A
  • more flexible
  • avascular
  • less organized structure
  • no nerve fibers
  • composed of up to 80% water
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how do nutrients get into the cartilage?

A

via perichondrium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the perichondrium made of?

A
  • fibrous connective tissue sheath
  • type I collagen
  • vascular supply
  • chondrogenic cells
  • no present in all types of cartilage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are the 3 types of cartilage in the body?

A
  • Hyaline-along axial skeleton
  • Fibrocartilage-meniscus, pubic symphisis, and intervertebral disks
  • Elastic cartilage-external ear, and epiglottis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

fiber types in hyaline cartilage

A

type II collagen fibers only

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

fiber types in fibrocartilage

A

type I and II collagen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

fiber types in elastic cartilage

A

elastic fibers, and type II collagen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what does chondoitin sulfate, a proteoglycan, do in cartilage?

A

provides much of the resistance to compression via electrostatic repulsion
*loss of chondoitin leads to osteoarthritis *

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

collagen II bound to proteoglycan aggregates made up of chondroitin sulfate linked to hyaluronic acid is what provides repulsion force in you cartilage? T/F

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

hyaline cartilage

A
most widespread type of collage
weakest of the three types of collagen
looks like frosted glass
*has a perichondrium
*has spherical chondrocytes
*made of type II collagen
*no nerves or blood vessels
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Fibrocartilage

A

strongest of all the cartilages

  • contains both type I and II collagen
  • more fibers than cells
  • lacks a perichondrium
  • highly compressible
  • menisici of knee, intervetebral discs, and pubic symphysis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Elastic cartilage

A

resembles hyaline cartilage but is more springy

  • contains collagen type II and elastic fibers
  • has a perichondrium
  • only found in external ear and epiglottis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

axial skeleton composition

A

skull, vertebrae, ribs and sternum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

five functions of bone

A
support
protection
assist in movement
mineral homeostasis
blood cell production
17
Q

Bone compared to cartilage

A
  • both contain living cells with occupy cavities called lacunae
  • contain a fibrous connective tissue covering
  • bone is highly vascularized
  • bone contains more collagen
  • all bone growth is by apposition or by deposition on an already existing surface
18
Q

adult bone is composed lamellae and are arranged to form types of bone

A

compact or cortical-most of bone in body 80%

trabecular or spongy 20%

19
Q

what do osteoclasts do?

A

bone resorption(breakdown) by creating SEALING zones and in part lowers the pH which dissolves hydroxyapatite and collagen.

20
Q

do osteoblasts build or break down bone?

21
Q

Bone calcium is available from two reservoirs, what are they?

A

exchangeable and stable. Most is in the stable form and is released slowly where the exchangeable is readily available

22
Q

where are the four places we get calcium and phosphorus from?

A

bone, kidneys, GI and diet.

*most of the calcium and phosphate in the body is in the bone

23
Q

parathyroid hormone (PTH)

A
  • secreted by chief cells of the parathyroid gland
  • mobilizes calcium from bone and increases calcium in blood
  • increases urinary phosphate excretion and *increases calcium reabsorption
24
Q

1,25-dihydroxycholecalciferol

aka calcitriol

A

is a steroid hormone formed from Vit. D n skin via the sun and successive hydroxylations in the liver and kidneys

  • increases calcium absorption form the intestine
  • increases calcium in bone
25
Calcitonin
lowers the calcium in blood via * inhibiting bone resorption(breakdown) * inhibiting calcium absorption by the intestine * stimulates osteoblastic activity in bones * inhibits reabsorption of calcium in kidney - secreted by the parafollicular cells in the thyroid gland
26
regulatory feedback between Vit D and PTH
- PTH helps activate Vit D to 1,25-dihydroxycholecalciferol in kidney - then it can down regulate PTH release
27
osteopetrosis
osteoclasts are defective and unable to resorb bone, so osteoblasts operate unopposed. bone over growth
28
osteoperosis
relative excess of osteoclast function results in loss of bone matrix and high risk of bone fractures. two causes: age and bisphosphinates(inhibit osteoclast activity, preventing resorbtion and increasing mineral content of bone.