| back 5 mature osteoblasts
- Maintain bone tissue
- No longer
secrete matrix |
| back 6 bone crushing cells.
- Originate from fused monocytes (type of WBCs) |
| back 7 the shaft or body of a
long bone |
| back 8 form the distal and
proximal ends of a long bone |
| back 9 the areas where the
epiphysis and diaphysis join (slide 6 for pic) |
| back 10 the end of active growth in the
epiphysis of the long
bones
which contains hyaline cartilage
- The growth plate is
always
actively dividing and causing The bone
to elongate
from each
end.
- In adults, the epiphyseal cartilage is
no
longer present and elongation of bones
has stopped. |
| back 11 Dense outer layer with few internal spaces
– Forms most of the
shaft of long bones (arms, legs)
– Solid, hard, external layer of
bone
– Resists stresses of weight & movement |
| back 12 Contains blood vessels, nerves, and cells involved in bone growth and
repair
• Injury to the periosteum (bruise, fracture) generates
pain
• It contains osteoblasts help the bone grow in thickness,
but not in length. |
| back 13 The structural unit of compact bones -Consists of;
osteocytes
(living bone cells) arranged in concentric rings (Lamellae) around a
central canal .
Each osteocyte lies within a lacuna (small space
within the hard matrix). Canaliculi Tiny canals
connect nearby
lacunae and the central canal Nutrients, oxygen, and wastes pass from
cell to
cell, traveling to and from the blood vessels in the
central canal |
| back 14 Latticework of bone
– Found in small, flat bones (skull) and in
the head and near the ends of the shafts of long
bones
– In
adults
• The spaces of some spongy bones are filled with red
marrow where blood cells
production (Hematopoiesis) take
place.
• The cavity in the shaft of long bones is filled with
yellow marrow,
a fatty tissue for energy storage |
| back 15 space within the
diaphysis of long bones that contains
fatty
yellow bone marrow in adults.
• The endosteum is a
membrane that lines the
medullary cavity .
• The endosteum
is composed of osteoclasts,
osteoblasts, and connective tissue. |
| back 16 25% water, 25% organic proteins, 50%
mineral salts Organic
constituents
• Collagen fibers provide flexibility and
tensile
strength.
• Mineral salts:
– Calcium Phosphate
(Ca3PO4)2
– Calcium Carbonate (CaCO3 - marble)
– Other trace
elements: magnesium, fluoride,
sulfate |
front 17 The transformation from cartilage to a long
bone (slide 14) | back 17 egins when osteoblasts form a collar of bone
around the shaft of
the cartilage model
– Osteoblasts then migrate to the bone cavity
to form
spongy bone
– Cartilage cells within the growth
plate divide, forcing
the end of the bone farther away from the
shaft
– As bone replaces the newly formed cartilage in
the
region closer to the shaft, the bone lengthens
– The
bone diameter also enlarges as the bone
lengthens
• Two
regions of cartilage remain at each end of
the long bone
–
The cap that covers the surfaces that rub against
other
bones
– The growth plate, also called the epiphyseal plate |
front 18 Parathyroid hormone (PTH) | back 18 released from the parathyroid glands increases blood
calcium
levels by
- release of calcium from bone.
-increase calcium
reabsorption from kidney.
-stimulate kidney to produce active
form of vit D which is important for
absorption of dietary
calcium.
- increase calcium absorption from intestine |
| back 19 released from the thyroid gland decreases blood calcium levels |
| back 20 stimulates bone growth during childhood |
| back 21 ensure that the skeleton grows with the proper proportions |
| back 22 (testosterone and estrogen)
prompt and stop the growth spurt of
puberty
By the end of the teenage years, sex hormones initiate
less frequent cell division
– Growth plate thins
– Ends of
the bone fuse with the shaft
– Bone can no longer increase in length |
| back 23 When a bone breaks, bleeding occurs and a clot
forms
•
Fibroblasts invade the clot and secrete collagen
fibers that form
a callus linking the two parts of
the bone
• Osteoblasts
transform this cartilage into bone |
| back 24 Bone remodeling repairs tiny cracks and regulates blood calcium
levels
• Two antagonistic hormones are involved
– Calcitonin
released from the thyroid gland decreases blood calcium levels
•
Parathyroid hormone (PTH) released from the parathyroid glands
increases blood calcium
levels
• In women, estrogen also
plays a role in bone remodeling
– Enhances the absorption of
calcium from the digestive system
– Stimulates the formation of
bone
– Inhibits the breakdown of bone
• Osteoporosis results
when bone is broken down faster than it is deposited |
| back 25 Before and shortly after birth,
the bones of the cranium
are
connected by membranous
areas called fontanels - gone by 2 |
| back 26 Excitable (they respond to stimuli)
– Contractile (they can
shorten)
– Extensible (they can stretch)
– Elastic (they can
return to their original length after being shortened or stretched |
| back 27 Moving our body
– Maintaining posture
– Pushing against
veins and lymphatic vessels to move blood and lymph along
–
Generating heat |
front 28 the names of the internal structures of the muscle fiber | back 28 Sarcolemma
• Sarcoplasm
• Myofibril
• T-tubules
•
Sarcoplasmic reticulum
(Calcium storage)
• Sarcomere |
| |
| back 30 a form of smooth endoplasmic
reticulum found in muscle cells
which
stores calcium ions. |
front 31 Transverse tubules (T tubules) | back 31 Pockets in the plasma membrane of a
muscle cell
– Carry
signals from motor neurons
deep into the muscle cell to
every
sarcomere
Skeletal Muscle |
| back 32 Surrounding the entire muscle
• Outer surface grades into the
fascia
• Inner surface sends projections between fascicles to form
perimysium |
| back 33 Wrap each fascicle
• carry larger nerves and blood vessels,
and
stretch receptors |
| back 34 Loose
connectiv
e tissue
surroundi
ng each
muscle
fiber |
| back 35 Actin filaments slide past
myosin filaments,
shortening the
sarcomere. It
is covered by troponin-
tropomyosin
complex.
– Myosin molecules are
shaped like two-headed
golf
clubs. The club-shaped
myosin heads are key
to
moving actin filaments |
| back 36 When a muscle is
relaxed, the troponin-
tropomyosin
complex
covers the actin-myosin
binding sites
• Muscle
contraction
occurs when calcium
ions bind to
troponin,
causing it to change
shape
• This change in
shape
moves tropomyosin,
exposing the actin-
myosin
binding sites |
| back 37 A junction between two nerve cells, consisting of a minute gap
across
which impulses pass by diffusion of a neurotransmitter |
front 38 ATP sources for muscle contraction | back 38 typically
used in sequence
– ATP stored in muscle
cells
– Creatine phosphate stored in muscle cells
–
Anaerobic metabolic pathways
– Aerobic respiration |
| back 39 Enough oxygen is delivered to the muscles to keep them going for long
periods
– Increases endurance and coordination
– Promotes
development of new blood vessels
– Increases the number of
mitochondria
– Typically does not increase size of muscles
–
Examples: walking, jogging, swimmin |
| back 40 Builds strength
– Muscles increase in size when they are
repeatedly made to exert more than
75% of their maximum
force
– Increases in muscle size reflect increases in the
diameter of existing muscle
cells
– Example: weight lifting |