Unit 3, Compendium 2

Muscular & Bone Systems

1.Muscle

a) 3 types of muscle tissue

b) Skeletal muscles

2.Anatomy of skeletal muscles

a) gross anatomy

b) micro-anatomy

c) myofilaments

3.Contractions

a) neuromuscular junction

b) synaptic knob

4.Action Potential Sequence

a) release of ACh

b) binding of ACh

c) conduction of action potentials

5.Bones

a) osseous tissue

b) calcium phosphate

c) osteocytes

d) osteclasts

e) osteoblasts

6.Remodeling & Homeostatic mechanisms

a) remodeling

b) calcium

c) fracture repair

1.Muscles

a) 3 types of muscle tissue: Skeletal, cardiac, and smooth muscle.

picture of the make up of muscle. http://fig.cox.miami.edu/ >>>>>>>>>>>>>>>>

b) Skeletal muscles attach to bones directly or indirectly, and are used to produce skeletal movement, maintain posture and body position,support tissues, guard entrances and exits, and maintain body temp.

2.Anatomy of skeletal muscles

a) Gross anatomy: Muscle fiber is surrounded by endomysium, sheathed by a perimysium, and covered by an epimysium. At the end of the muscle is a tendon.

b) Micro anatomy: Muscle cells have a sarcolemma, sarcoplasm, and a sarcoplasmic reticulum.

c) Myofilaments consit of a thin filament(actin) and a thick filament(myosin).

3.Contractions

a) Neuromuscular Junction: The link between electrical activity in the sarcolemma and the initiation of a contraction.

b) Synaptic knob, synaptic cleft, and motor end plate are part of the junction. picture of neuromuscular junction http://abdellab.sunderland.ac.uk/ >

4. Action Potential Sequence

a) The release of acetylcholine (ACh): Impulse at synaptic knob release ACh into synaptic cleft.

b) The binding of ACh at motor end plate: This event changes the permeability of the membrane to sodium ions.

c) This conduction of action potentials by the sacrolemma: This triggers a sudden release of calcium ions. The ens result is a contraction. This is how our body achieves movement.

5.Bones

a) Osseous tissue: Supports connective tissue, contains specialized cells, extracellular fibers, and ground substances. end product is a distinct solid with a stony character from the disposition of calcium salt. picture of bone tissue http://medicalimages.allrefer.com/ >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

b) Calcium Phosphate(Ca3(PO4)2: Accounts for 2/3 of the weight of bones. The remaining 1/3 is dominated by collagen fibers.

c) Osteocytes: Mature bone cells that recycle calcium and assists with bone repairs.

d) Osteoclasts: Giant cells with 50 or more nuclei, helps regulate calcium and phosphate concentrations in the bodies fluid.

e) Osteblasts: Cells responsible for the production of new bone.

6.Remodeling & Homeostatic mechanisms

a) Remodeling: Organic and mineral components of bone are continuously recycled and renewed.

b) Calcium: Most abundant mineral in the body. 99% is located in the skeleton, which acts as a calcium reserve for the body.

c) Fracture repair involves the formation of a fracture hematoma.

d) effects of aging on the skeleton can include osteopenia and osteoporosis.

picture of remodeled bone http://www.osteopeak.com/ >>

references: Aris, Mader book, Brady book.