Class notes
BIOL 102 Lecture 5 - 10 Notes
- Course
- BIOL 102
- Institution
- Liberty University
This is a comprehensive and detailed note that covers lectures 5-10. *Essential!!
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CHAPTER 5 --- SkeletalSkeletal system: made of connective tissue
Bone: Hard inorganic matrix of calcium salts
Compact: forms shaft and ends, contains marrow space (yellow marrow = fat
marrow)
(Red marrow produces blood cells and is in the ends of the bones)
Spongy: trabecular
Cells
o Osteoblast (change cartilage into bone in the fetus)
o Osteocytes: Osteons/Haversian system: cellular arrangement
(mature bone cells that maintain the structure of bone)
o Osteoclast (bone-dissolving cells)
4 Types of Bones
Long (limbs/finger)
Short (bones of the wrist)
Flat (sternum, ribs, cranial bones)
Irregular (coxal)
Periosteum: CT covering
Diaphysis - outside hard part of yellow bone, blood vessel
Epiphysis - spongy bone/ red marrow
Cartilage and Ligaments
Cartilage
o Function: support
o Types: fibrocartilage, hyaline, and elastic cartilage
Ligaments: attach bone to bone
Bone Development
Prenatal: cartilage model
Fetus: some conversion to bone
Childhood: primary and secondary ossification sites formed
Adolescence: cartilage growth plate elongates
Mature Bone Remodeling and Repair
Changes in shape, size, strength
o Dependent on diet, exercise, age
Bone cells regulated by hormones
o Parathyroid hormone (PTH): removes calcium from bone
o Calcitonin: adds calcium to bone
Repair: hematoma and callus formation
Human Skeleton
206 bones
Axial Skeleton - skull, vertebral, column, ribs, sternum (anything attached to the
spine)
Appendicular Skeleton - Pectoral girdle, pelvic girdle, limbs
Functions of the skeletal system
, Protection: encases most internal organs
Support: allows body positions
Permit movement: muscle attachments for movement
Mineral Reservoir: calcium, phosphorus
Vertebral column
First 7: Cervical Vertebrae – (CV1-CV7)
Smallest of the vertebrae
Neck
C1 called atlas – holds skulls up, nod
C2 called axis – rotates head
Next 12: Thoracic Vertebrate – (T1-T12)
Where ribs attach
Next 5: Lumbar Vertebrae
Lower back
Biggest 5
Next 5: Sacrum
Lower back
Last 4: Coccyx
Butt
Axial Skeleton
Vertebral column
o Regions: cervical, thoracic, lumbar, sacral, coccygeal
o Intervertebral disks: cushion the vertebrae, assist in movement/
flexibility
Ribs
o 12 Pairs
o Bottom two pair floating
Sternum: breastbone
o 3 bones fused together
Appendicular Skeleton: Appendages, anything not attached to the spine
Pectoral girdle: Shoulder
o Clavicle and scapula
Pelvic girdle: hip:
o Coxal bones, sacrum, pubic symphysis
Limbs
o Arms: humorous, radius, ulna, wrist and hand bones
o Legs: femur, tibia, fibula, ankle, and foot bones (fibula smaller than
tibia)
Joints (articulations)
Classified by degree of movement
Three types of joints
o Fibrous joint: immovable (fontanels)
o Cartilaginous joint: slightly movable, cartilage connection (backbone)
o Synovial joint: freely movable (hinge joint - knee, elbow)
, Synovial Joints
Joint capsule: synovial membrane & hyaline cartilage
Synovial membrane secretes synovial fluid as a lubricant
Hyaline cartilage acts as a cushion
Types of synovial joints
o Hinge joint
o Ball and socket joint
Tendons: join bone to muscle
Diseases and Disorders of the Skeletal System
Sprains: stretched or torn ligaments
Bursitis and tendinitis: inflammations (itis means inflammation)
Arthritis: inflammation of joints
o Osteoarthritis: wearing down of the joint
o Rheumatoid arthritis: due to allergy
Osteoporosis: excessive bone loss
CHAPTER 6 --- Muscles
Muscle Function: Produce movement or generate tension
Principle Function
Contraction: shortens the distance between bones
Skeletal muscle moves bones
Muscle Groups
Synergistic: groups work together
Antagonistic: groups oppose each other
Muscle Structure
Fasicles
o Bundles of muscle fibers wrapped with connective tissue (fascia)
Muscle Fibers (muscle cells)
o Long, tube shaped cell
o Multinucleate
o Packed with myofibrils (smaller)
Myofibrils contain actin & myosin (proteins)
Skeletal Muscle Contractive Unit
Sarcomere: Contractive Unit
Myosin: Forms think filaments
Actin: forms thin filaments
Z lines: attachment points for sarcomeres
Arrangement of filaments gives rise to striated appearance of skeletal muscle
Nerve Activation of Individual Muscle Cells
Acetylcholine released from motor neuron at neuromuscular junction
Electrical impulse transmitted along T tubules
Calcium released from sarcoplasmic reticulum
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