Musculoskeletal system Flashcards
What are the general functions of the musculoskeletal system?
Support, protect, allow movement
Where are mechanical forces generated by muscle contraction typically transmitted?
To skeletal structures of chitin or bone to produce motion.
What type of skeletons do invertebrates have?
Hydrostatic skeletons or exoskeletons
What type of skeletons do vertebrates have?
Endoskeletons
What are hydrostatic skeletons?
The fluid-filled body compartments of many soft-bodied invertebrates
What are examples of animals with hydrostatic skeletons?
Cnidarians, flatworms, annelids, and roundworms, sea anemones, earthworms, and other invertebrates
How do hydrostatic skeletons work?
Fluid is held under pressure in the body; when muscles in the compartment wall contract, they push against the tube of fluid. The force is transmitted through the fluid, changing the shape and movement of the body
What is the fluid-filled compartment present in animals with hydrostatic skeletons called?
Coelom
Why are hydrostatic skeletons called hydrostatic?
The compartment is under hydrostatic pressure because of the fluid, and supports the other organs of the organism.
How do hydrostatic skeletons work in cnidarians?
Two body layers work in antagonistic fashion—contraction of the epidermal layer causes shortening; contraction of the inner layer causes lengthening
What kind of skeleton do sea stars and sea urchins have?
They have an endoskeleton, but they move their tube feet using a type of hydrostatic skeleton.
How do hydrostatic skeletons work in earthworms?
In annelid worms (earthworm), septa isolate portions of the body cavity, allowing the hydrostatic skeletons of each segment to be largely independent of one another.
What do most animals do in regard to their skeletons?
Most animals deposit a nonliving, protective exoskeleton over their outer epithelium.
Why do animals with exoskeletons have to shed?
Because exoskeletons are acellular and don’t grow
What type of skeleton do sharks and rays have?
Cartilage endoskeletons
Echinoderms and chordates have internal skeletons consisting of what?
Plates or shafts of living tissue (such as cartilage or bone).
The echinoderm endoskeleton consists of what?
Spines and plates of calcium salts embedded in the body wall, beneath the epidermis like an internal shell.
What are the two sections of the vertebrate endoskeleton?
Axial and appendicular
Describe the axial skeleton
Located along the central axis of the body; consists of the skull, vertebral column, ribs, and sternum (breastbone)
Describe the appendicular skeleton
Bones of the limbs (arms and legs), and bones of the pectoral (shoulder) girdle and pelvic (hip) girdle, which connect the limbs to the axial skeleton
What does the axial skeleton consist of?
The skull, ossicles of the middle ear, the hyoid bone, the vertebral column, and the thoracic (rib) cage
Describe the vertebral column (How many vertebrae of each type?)
24 vertebrae: 7 cervical, 12 thoracic, 5 lumbar; and 2 bones composed of fused vertebrae, the sacrum and coccyx.
The rib cage consists of what?
The sternum, thoracic vertebrae, and (in mammals) 12 pairs of ribs.
What does the skull consist of? What does it do?
The cranial and facial bones which protect the brain and form the face.
What do spinal curves do?
Increase the strength and flexibility of the spine.
What does the thoracic (rib) cage do?
Protects the lungs and heart
Each human limb consists of what?
30 bones and terminates in 5 digits (fingers/toes)
What does the pectoral girdle consist of?
2 collar-bones (clavicles) and 2 shoulder blades (scapulas)
What do the upper limbs consist of?
Humerus of the upper arm, radius and ulna of the forearm, eight bones of the carpus, five bones of the metacarpus, and 14 bones of the phalanges
What are the scapulas (shoulder blades) attached to and how?
Loosely attached to the vertebral column by muscles
What does the pelvic girdle consist of?
A pair of large bones fused to the vertebral column
What does each large bone of the pelvic girdle consist of?
Each large bone is 3 fused hipbones: illium, ischium, pelvic bone
What do the lower limbs consist of?
The femur of the thigh, Patella (kneecap), Tibia & Fibula of the leg, 7 tarsal bones of the ankle, 5 metatarsals, 14 phalanges