chapter 8 - purely skeletal system Flashcards
list the functions of the skeleton
- provides a scaffold to support the weight of the rest of the body
- facilitates movement by being points of attachment for muscles
- protection of vital internal organs
- produces RBC’s
- stores and releases minerals and fats
how many bones make up the adult human skeleton?
206
what are the two sections that bones of the skeleton are divided into?
the axial skeleton and the appendicular skeleton.
what is the axial skeleton?
bones that lie around the central axis of the body
what is the appendicular skeleton?
bones of the upper and lower limbs
what are the 5 different types of bones?
- long bone
- short bone
- irregular bone
- flat bone
- sesamoid bone
long bone
supports weight and allows movement
eg. femur
short bones
provide stability and some movement
eg. intermediate cuneiform, lateral cuneiform, medial cuneiform
irregular bone
variable nature helps to protect different structures
eg. vertebrae
flat bone
protects internal organs
eg. sternum
sesamoid bone
protects tendons
eg. patella
what are the three distinct parts of long bones
- diaphysis - shaft making up the main portion of the bone - cavity acts as a fat storage sight and is called the yellow bone marrow. (WBC’s are produced here)
- epiphyses - enlarged ends of the bone, covered in a thin layer of cartilage. compact bone on outside but spongy/ cancellous bone on the inside. (RBC’s are produced here)
- periosteum - dense, white, fibrous outer covering of the bone.
microscopic structure of bone
- bone is classified as a connective tissue (cells separated from each other by large amounts of non-cellular material called matrix)
- in bone, inorganic salts of calcium and phosphate are deposited in the matrix, increasing its rigidity and strength.
microscopic structure of compact bone
the consist of units called osteons, which run parallel to the long axis of the bone, giving the bone maximum strength.
description: consist of osteons with concentric layers of lamellae.
microscopic structure of spongy bone
also called cancellous bone
it consists of thin, bony, irregular plates called trabeculae
- bone cells occupy spaces in the trabeculae, and nerves and blood vessels pass through irregular spaces in the matrix.
structure of cartilage
it is a connective tissue
it contains numerous fibres made up of a protein called collagen. these fibres are embedded in a firm matrix of a protein-carbohydrate complex called chondrin.
what does chondrin do for the bone?
chondrin allows cartilage to function as a structure of support.
what does collagen do for the bone?
the presence of collagen fibres gives the cartilage a certain degree of flexibility.
explain the process of cells maturing, becoming chondrocytes
cartilage has a firm matrix in which collagen fibres are embedded. within the matrix are spaces that contain cartilage cells called chondroblasts.
- these cells produce matrix and gradually become surrounded until they are surrounded in small spaces called lacunae.
- once this has occurred, the cells are considered to be mature and called chondrocytes
what are the three types of cartilage?
hyaline cartilage, elastic cartilage and fibrocartilage
describe hyaline cartilage and provide an example
- so fine that they’re not distinguishable under a light microscope
- closely packed fibres throughout the matrix
eg. rings of the trachea and bronchi + articular cartilage
describe elastic cartilage and provide an example
- clearly visible elastic fibres and very fine collagen fibres (like hyaline), but not so closely packed
eg. external ear
describe fibrocartilage and provide an example
- parallel bundles of thick collagenous fibres make up the tissue, causing its coarse appearance
- not as compact as hyaline cartilage and able to be compressed slightly
eg. intervertebral discs in the spinal column, meniscus of the knee joint, tissue joining two sides of the pelvis
additional facts about cartilage
- does not contain blood vessels
- all nutrition and waste removal from the cells depends on diffusion through the matrix
- this is a slow process and the reason why some injured cartilage takes some time to heal
joints are classified according to…?
- the range of movement they allow (functional classification)
- the type of connective tissue that binds the bones together (structural classification)
what are the three types of joints?
fibrous, cartilaginous and synovial
what are fibrous joints?
(immoveable)
- no movement occurs between the bones
- bones held in place by fibrous connective tissue
eg. skull or between the teeth and jaw
what are cartilaginous joints?
(slightly moveable)
- held in place by cartilage, allowing slight movement
eg. junction of the two pelvic bones (pubis symphysis), joints between adjacent vertebrae, joints between ribs and sternum
what are synovial joints?
(freely moveable)
- amount of movement is limited by ligaments, muscles, tendons and adjoining bones
eg. shoulder, elbow, wrists, fingers, hips, knees, ankles and toes
types of synovial joints
- ball and socket joints
- hinge joints
- pivot joints
- gliding joints
- saddle joints
- condyloid joints
ball and socket joints
- when the spherical head of one bone fits into a cup-like cavity of another
- eg. head of the humerus fits into a depression in the scapula or head of the femur articulates with the pelvis
hinge joints
- allow movement in one plane only (like the hinge of a door)
- concave surface of one bone fits into the concave surface of another
- eg. the elbow and knee are the best examples
- other examples include the ankle and between the bones of the fingers and toes
pivot joints
- formed by rounded, pointed or conical end of one bone articulating with a ring
- joint between the first vertebrae and the second vertebrae (allows the head to rotate)
- between the radius and the ulna of the forearm (allowing rotation of the hand)
gliding joints
- allow movement in one direction in a side to side or back and forth motion, restricted only by ligaments
- found between carpal bones, tarsal bones, the sternum and clavicle, the scapula and clavicle
saddle joint
- the only true saddle joint is where the thumb joins the palm of the hand
- two bones forming the joint are both saddle shaped (concave in one direction and convex in the other)
- fit together in such a way that they allow side to side and back and forth movements
condyloid joints
- have one surface of bone slightly convex that fits into a slightly concave depression in another bone
- allow movements in two directions
- occur between radius and carpal bones, metacarpal bones and phalanges of fingers, between the metatarsal bones and phalanges of toes.
what allows a synovial joint to move freely?
the structure of the synovial joint, including the synovial capsule, fluid and articular cartilage
provide 4 functions of synovial fluid
- lubricates
- helps keep the articulating surfaces from making contact with each other
- provides nourishment for the cells of the articular cartilage
- contains phagocytic cells that remove microorganisms and debris resulting from wear and tear of a joint
articular cartilage
smooth surface for movement
articular discs (menisci in knee)
direct fluid to areas of a greatest friction
bursae
prevent friction between a bone and a ligament or tendon and a bone and the skin where a bone inside a joint capsule is near the body surface
ligaments
hold the joints together in many joints
flexion vs extension
flexion = decreases the angle of articulating bones extension = increases the angle between articulating bones
rotation
the movement of a bone around its long axis
how many cervical vertebrae are there?
7
how many thoracic vertebrae are there?
12
how lumber vertebrae are there?
5
what are the three types of ribs and how many are there of each?
true ribs: 7 (ribs 1-7)
false ribs: 3 (ribs 8-10)
floating ribs: 2 (ribs 11-12)
