Other Important Bones THE SKULL

made of the hyoid, cranial bones (8), and facial bones (14)
baby's skull has fontanels, which are membranous portions (or soft spots) so they can be birthed easier but eventually close
contains large orbits for eyes, a pronounced forehead and small face

THE VERTEBRAL COLUMN

made of 3 division of vertebrae (cervical, thoracic and lumbar)
the sacrum is made of fused vertebrae in the pelvis
the coccyx is a small tailbox at the end of the sacrum

THE THORACIC CAGE

protects the heart and lungs
12 pairs of ribs, but the first 7 are TRUE ribs and last 5 are FALSE ribs

THE PECTORAL GIRDLE

made of the scapula and clavicle
connects upper limbs to the skeleton, and aids movement

THE PELVIC GRIDLE

the girdle is made of 2 hipbones (the coxae)
if you add the sacrum and coccyx, the pelvis is formed

UPPER LIMBS

humerus, radius, ulna in upper arm
hand made of 8 carpals, 5 metacarpals, and 14 phalanges

LOWER LIMBS

femur, tibia, fibula with patella bone in upper leg
ankle/foot made of 7 tarsals, 5 metatarsals, and 14 phalanges

Chapter 8: Muscular System Smooth Muscle

found in the stomach wall and esophagus, etc.
unstriated
involuntary
1 nucleus per cell

Cardiac Muscle

found in the heart
striated
involuntary
1 nucleus per cell

Diseases Affecting Muscles MUSCULAR DYSTROPHY is when proteins are missing, causing weakened muscles that degenerate over time. Duchenne's muscular dystrophy only affects boys, who will die in early adulthood.

CHARCOT-MARIE-TOOTH DISEASE is caused by a duplicate gene that impairs myelin formation, that causes a slow progression of symptoms that resemble AIDS, diabetes and vitamin deficiency.

MYOTONIC DYSTROPHY delays muscle relaxation following a contraction, which can cause irregular heartbeats or facial muscle weakness. It gets inherited genetically and worsens with subsequent generations.

HEREDITARY IDIOPATHIC DILATED CARDIOMYOPATHY is a very rare form of heart failure caused by the inability of action to anchor to Z lines in heart muscles, the chambers of the heart enlarge and not function leading to a 50% lethality rate.

Steps of a Muscle Contraction 1. RELEASE OF ACETYLCHOLINE
The neurotransmitter of acetylcholine moves down nerve impulses to bind to the motor plate.
2. MUSCLE IMPULSE
The impulse is stimulated and spreads into muscle tubules.
3. MOVEMENT
Cisternae become more permeable and want to take calcium, meanwhile calcium moves out of the sarcoplasmic reticulum TO THE SARCOPLASM.
4. EXPOSING AND BINDING
High calcium in sarcoplasm causes the actin to want to bind to TROPONIN and TROPOMYOSIN.
5. CONTRACTION
The myosin heads pull on the actin, and the ATP fuels the myosin meaning the contraction lasts as long as acetylcholine is present.
6. RELAXATION
Acetylcholine is broken down, and the calcium goes back into the sarcoplasmic reticulum.

	Criado por Courtney Merkel quase 9 anos atrás

Bones and Muscles