Transcript skeletal system - OCPS TeacherPress

The skeletal system
1. SUPPORT
• Attachment for tendon, framework for body
2. PROTECTION
• Ex: cranial bones protect brain
3. ASSISTANCE IN MOVEMENT
• Work with muscles
4. MINERAL HOMEOSTASIS
• calcium
5. BLOOD CELL FORMATION
• hemopoiesis in red bone marrow of select bones
6. TRIGLYCERIDE STORAGE
• Potential energy reserve in adipose cells of yellow bone
marrow
• 1. diaphysis: shaft
• 2. epiphyses: ends
• 3. metaphysis: between
diaphysis and epiphysis.
Contains epiphyseal
plate (hyaline cartilage)
in growing bone.
Replaced by bone
around 18-21 =
epiphyseal line
4. Articular cartilage: covers
ends of bone to reduce
friction
• 5. periosteum: surrounds
bone everywhere there
isn’t articular cartilage;
bone growth in thickness,
• assists in fracture repair,
serves as an attachment
point for ligaments and
tendons
7. endosteum: lines the
medullary cavity
6. Medullary cavity (marrow cavity):
inside diaphysis that contains fatty
yellow bone marrow
Compact bone tissue
• Strong/light
• Makes up most of
diaphysis
Parts of compact bone
OSTEON: repeating unit of
the structures
1. Perforating
(Volkmann’s) canals:
transverse, for blood
vessels and nerves
2. Central (haversian)
canals: connect with
perforating canals; run
longitudinally; for blood
vessels and nerves
3. Concentric lamellae: rings
around central canals
4. Lacunae: spaces between
lamellae
5. Canaliculi: fluid-filled;
radiating from lacunae in all
directions.
Spongy bone tissue
Does NOT
contain osteons
Sometimes
red
bone marrow
Forms most of
epiphyses and
narrow rim around
medullary cavity
of diaphyses
Looks spongy;
is not soft
Makes up most
of short, flat, and
irregulary shaped
bones
Choices: spongy or compact
1. What type of bone tissue is made up of
osteons?
2. What type of bone tissue would the
patella be made up of?
Calcium in bone
• Bones, neurons, muscle cells, blood
clotting, depend on Ca+2 in blood.
• Too high – heart stops
• Too low – osteoporosis, breathing
stops
Calcium homeostasis
• Stimulus: low blood calcium levels
• Receptors: cells of parathyroid gland
• Control center: nucleus of parathyroid cells
(parathryoid hormone – PTH)
• Effectors: osteoclasts activated – releases
calcium from bone
A negative feedback system
• Stimulus: high blood calcium levels
• Receptors: Cells in thyroid gland
• Control center: nucleus of thyroid cells
(secrete calcitonin).
• Effectors: osteoclasts inhibited: bone
absorbs calcium
What type of feedback system?