Midterms - Lecture notes 5-10 PDF

Preview

Summary

anatomy and physiology lectures in midterms with different chapters...

Description

CHAPTER 7: SKELETAL SYSTEM FUNCTIONS OF THE BONES: The skeleton works with the muscle to produce movement. Human adult 206 bones. Nature has given us an extremely strong and exceptionally simple supporting system without giving up mobility. The bone is also called? Osseous – one of the hardest materials in the body and although relatively light in weight, it has a remarkable ability to resist tension and other forces acting on it. The calcium salts are deposited in the matric give bone its hardness which resists compression. The organic part especially the collagen fibers which also provide bone flexibility and great tensil strength. It means that the bones has the ability to be stretched without breaking. FUNCTIONS OF THE BONES Besides contributing to body structure, our bones perform several important body functions: • Support and framework • Protection Protection. • Allow movement movement. • Storage • Blood cell formation formation. Associated with the bones: 1. Cartilage Cartilage- connective tissue, is the environment in which bones develops in a fetus it is also found at the ends of a certain bones and in joints in adults, providing a smooth surface for adjacent bones to move against each other. Model for bone formation 2. Ligaments Ligaments- a tough connective tissue that attach bones to bones 3. Tendons – similar structure that attach muscle to bones.

Two types of ossification o Intramembranous Ossification - the dense connective tissue membranes are replaced by deposits of inorganic calcium salts, thus forming bones. o Endochondral Ossification - is a process in which cartilage is the environment which the bone cells develop.. Osteoblast – bone forming cells. MAINTAINING BONE BONE:: The proper calcium ion concentration in the blood and bones are controlled by endocrine system TWO HORMONES THAT CONTROL THE CALC CALCIUM IUM CONCENTRATION IN OUR BODIES. 1. Calcitonin – is produced by the thyroid gland, it causes calcium to be stored in the bones. 2. Parathormone – produced by the parathyroid glands, it causes calcium to be released in the bloodstream. BONE GROWTH AND REMODELING

Appositional growth – the process by which bones increase in diameter. Osteoclasts – are giant bone-destroying cells in bones, to break down bone matrix and release calcium into the blood. Two types of bone tissue 1. Compact (cortical) bone: A hard outer layer

Bone formation: Ossification – the process of bone develop using hyaline cartilage structures as their “models” except for flat bones which form on fibrous membrane.

that is dense, strong, and durable. It makes up around 80 percent of adult bone mass. Outer bone and rigid. DENSE TISSUE. Dense and rigid it looks smooth and homogenous.

Location: outer part of diaphysis (long bones) and

generally cube-shaped and contain most spongy

thinner surfaces of other bones.

bone. Example: Carpal bones.

OSTEON or HAVERSIAN CANAL – is the

Flat bones: Usually bones that are thin, flattened

structural unit of compact bone. This system allows

and curved. They consist of two outer layers of

for the effective metabolism of bone cells

compact bone and an inner layer of spongy bone.

surrounded by rings of mineral salts. Includes the

Flat bones include most of the bones of the skull

lamella, lacunae, canaliculus, central canal,

and the sternum or breastbone. They tend to have

osteocytes.

a protective role. Example: sternum, ribs, scapula,

LAMELLA – rings of bone matrix.

and cranial bones.

LACUNAE – spaces between lamella.

Sesamoid bones: These are embedded in tendons,

CANALICULUS - tiny canals that transport

such as the patella or kneecap. They protect

the nutrients and remove waste. CENTRAL CANAL - is the center of Osteon that contain blood vessels

tendons from wear and stress. Are small rounded bones these bones are enclosed in tendon and fascial tissue and are located adjacent to joints. They assist in functioning of muscles. Example:

2. Cancellous (trabecular or spongy)

kneecap

bone: Composed of small needle like pieces

Irregular bones: As their name implies, these are

of bones and lots of open spaces. It is in

bones that do not fit into the first four categories

these spaces that bone marrow can be

and are an unusual shape. They include the bones

found. Is the inner bone and porous.

of the spine and pelvis. They are often protecting

Cancellous bone.

organs or tissues. Are bones do not fit one of the

Location: epiphyses of long and center of other bones. Trabeculae – interconnecting rods, spaces contain marrow. Has no osteons. Bone marrow - The formation of red and white blood cells. 5 classification of bones according to shape Long bones: These are mostly compacted bone with little marrow and include most of the bones in the limbs. These bones tend to support weight and help movement. Are typically longer than they are wide. Have a shaft with heads at both ends. Mostly compact bones Short bones: Only a thin layer of compact bone, these include bones of the wrist and ankle. Are

preceding category.

GROSS ANATOMY OF LONG BONE

MICROSCOPIC ANATOMY OF THE BONE

Diaphysis or shaft - makes up most the bone length

Osteocytes – is the mature bone cells which found within the matrix in tiny cavities called lacunae. Lacunae – are arranged in concentric circles called lamellae around the central canal. Central canal or Haversian canal – is in the center of osteon and is the canal that run lengthwise through the bony matrix, carrying blood vessels and nerves to all areas of the bone. HOMEOSTATIC IMBALANCE OF BONE -Rickets is a disease of children in which the bones fail to calcify. As a result, the bones soften, and the weight bearing bones of the legs become bowed. Rickets is usually due to a lack of calcium in the diet or lack of vitamin D, which is needed to absorb calcium into the bloodstream. Bone Fracture – is the break in the continuity of the bones management: REDUCTION REDUCTION: is the alignment of the bone ends. After the broken bone reduced, it is immobilized by a cast or traction to allow the healing process to begin.

and is composed of compact bones. Periosteum – is a fibrous connective tissue that covered and protect the diaphysis. Perforating or sharpey’s fibers – a hundreds connective tissue that secure the periosteum to the underlying bone Epiphysis – are the ends if the long bone, each consists of a thin layer of compact bone enclosing an area filled with spongy bone. Articular cartilage – is a glassy hyaline cartilage that covers of each external surface of epiphysis. Epiphyseal line – are a thin line of bony tissue spanning the epiphyses. A remnant of the epiphyseal plate. Epiphyseal plate – a flat plate hyaline cartilage that seem on young, growing bone.

STAGES IN THE HEALING OF A B BONE ONE FRACTURE

Yellow marrow or medullary cavity – is the cavity of the shaft primarily a storage area for adipose tissue.

A fractured or broken bone undergoes repair through four stages: 1. Hematoma formation: 2. A fibrocartilage callus forms: 3. Bony callous formation: 4. Bone remodelling occurs: TWO DIVISION OF SKELETON - The skeleton is subdivided into two major divisions—the the axial and appendicular appendicular. Has 206 bones. THE AXIAL SKELETON - The axial skeleton form the longitudinal axis of the body. The axial skeleton of the adult consists

-

of 80 bones. There are 3 parts of axial skeleton, including the skull, the vertebral column, and the thoracic cage cage. Skull – o Cranial/cranium – encloses and protects the fragile brain. A boxlike cranium is composed of eight large flat bone. Except for two paired bones, the parietal and temporal which all single bones. ▪ Frontal bones – the bones that form the forehead, the bony projections under the eyebrows and the superior part of each eye’s orbit. ▪ Parietal bone – paired bones form most of the superior and lateral walls of the cranium. They meet in the midline of the skull at the sagittal suture, and form the coronal suture, were they meet frontal bone. ▪ Temporal bones – the bone that lie inferior to parietal bones, they joined them at the squamous suture. Several important markings appear on the temporal bone. -

-

Important bone marking at temporal bone: o External acoustic meatus – is a canal that leads to the eardrum and the middle ear, it is the route by which sound enters the ear.

o Styloid process – a sharp, needlelike projection, is just inferior to the external auditory meatus use these as an attachment. Located at the temporal bone. o Zygomatic process process- is a thin bridge of bone that joins with the check bone anteriorly. o Mastoid process – is a rough projection posterior and inferior to the external acoustic meatus. It provides an attachment site for some muscle of the neck. Because it is too close to the middle ear it is high risk for infection called mastoiditis. o Jugular foramen – located at the junction of the occipital and temporal bones and allows passage of the jugular vein, the largest vein of the head. o Internal acoustic meatus – located just anterior to the cranial cavity, which transmits cranial nerve VII (facial nerve) and cranial nerve VIII (vestibulochochlear) o Carotid canal – located anterior to the jugular foramen, through which the internal carotid artery runs, supplying blood to most of the brain. Occipital bone – is the most posterior bone of the cranium. It forms the base and the back wall of the skull. This bone joins the parietal bone anteriorly at the lambdoid suture. o Foramen magnum – is a large opening located on the base of the occipital bone. It surrounds the lower part of the brain and allows the spinal cord to connect with the brain. Occipital condyle – located lateral to o the foramen magnum, with each side are rockerlike, and rest of the first vertebrae of the spinal column.

O Sella turcica – is a small depression located in the middle of the sphenoid, which form a snug enclosure for the pituitary gland. O Foramen ovale – is a large opening in line with the posterior end of the sella turcica, which allows fibers of cn-v to pass to chewing muscles of the lower jaw. ETHMOID BONE – is a very irregularly shaped and lies anterior to the sphenoid. It forms the roof of the nasal cavity and part of medial wall of the orbit. O CRISTA GALLI – the outer most covering of the brain attached to this projection, on each side are many small holes. O CRIBRIFORM PLATES –is a holelt areas that allow nerve fibers carrying impulses from the olfactory receptors of the nose to reach the brain. O SUPERIOR AND MIDDLE NASAL CONCHAE – is the extensions of the ethmoid bone, which form as part of the lateral walls of the nasal cavity and increase the turbulence of air flowing through the nasal passages.

FETAL SKULL – the fontanels allow the fetal skull to be compressed slightly during birth. In addition, because they are flexible, they allow the infant’s brain to grow during the later part of pregnancy and early infancy. This would be possible if the cranial bones were fused in sutures as the adult skull. The fontanels are gradually converted to bone during the early part of infancy and can no longer be felt by 22 or 24 months after birth. O ANTERIOR FONTANEL – is a diamond-shape and is the largest fontanels. CRANIAL SUTURES – a suture is a type of fibrous joint that is only found in the skull. The bones are bound together by sharpey’s fibers. A tiny amount of movement is permitted at sutures, which contributes to the compliance and elasticity of the skull. These joints are synarthroses. O THERE ARE FOUR MAJOR SUTURES: O Sagittal suture – the joint between two parietal bones. O Coronal suture – the joint between the frontal bone and the parietal bones. O Squamous suture suture- the joint between the parietal and temporal bones. O Lambdoidal suture – the joint between the parietal bones and the occipital bone. FACIAL BONE 14 bones compose the face. 12 are paired only the mandible and Vomer are single. • Maxilla – the two maxillary bones, fuse to form the upper jaw. All facial bones except the mandible join the maxillae, thus they are the main or “keystone” (bcs lahat ng bones sa face ay naka dikit sa kanya) bones of the face. The maxillae carry the upper teeth in the alveolar process. o Palatine process – form the anterior part of hard palate of the mouth. • Palatine bones – the paired lie posterior to the palatine process of the maxillae, they form the posterior part of hard plate. Failure to these of the palatine process to fuse medially results in cleft palate. • Zygomatic bones – also known as the malar bones. This bone are commonly referred to as cheekbone. They also form a good-sized

portion of the lateral wall of the other orbits, or eye sockets. • Lacrimal bones – are finger nail sized bones forming part of the medial walls of each orbits. Each lacrimal bone has a groove that serves as a passageway for tears. • Nasal bones – the small rectangular bones forming the bridge of the nose are the nasal bones. • Vomer bone – the single bone is median line of the nasal cavity. The vomer form most of the bony nasal septum Inferior nasal conchae – are thin, curve • bones projecting medially from the lateral wall of the nasal cavity • Mandible – or the lower jaw, is the strongest bone of the face. It joins the temporal bones on each sides of the face, forming the only freely movable joints in the skull. The horizontal part of the mandible (the body) forms the chin. Two upright bars of the bones (the rami) extend from the body to connect the mandible with the temporal bone. The lower teeth lie alveoli in the alveolar process at the superior edge of the mandibular body. Temporomandibular joint • • • •

Zygomatic – cheek bones Mandible Mandible--- lower jaw Maxilla- upper jaw Hard palate - roof of the mouth

Paranasal SINUSES Normally sinuses are empty except for a thin layer of mucus. The mucus is there to protect the tissue of the sinuses from drying out. Sinuses has many function, including protecting the face from trauma. You can think of them like those air pillows that are used to protect fragile items during shipping 2.vertebral vertebral column – it extend from the skull, which it supports, to the pelvis, it transmit the weight of the body down to the lower limbs • Cervical vertebra • Thoracic vertebra • Lumbar vertebra

• Sacrum • Coccyx Intervertebral disc – a pads of flexible fibrocartilage which separate the individual vertebrae. It acts to cushion of the vertebrae and absorb shock while allowing the spine flexibility Homeostatic imbalance – scoliosis (posterior), kyphosis (lateral). all vertebra have a similar structural patter. The common features of vertebrae include the ff: Body or centrum – disclike, weigh-bearing part of the vertebrae facing anteriorly in the vertebral column • Vertebral arch – arch formed from the joining of all posterior extensions, the laminae and pedicles, form the vertebral body • Vertebral foramen – a canal through which the spinal cord passes. • Transverse processes – are two lateral projection from the vertebral arch • Spinous process – are single projection arising from the posterior aspect of the vertebral arch (actually the fused laminae) • Superior and inferior articular process – are paired projection lateral to the vertebral foramen, allowing a vertebrae to form joints with adjacent vertebrae. Specific structure of the spine • Ce Cervical rvical vertebrae – the seven cervical vertebrae (identified as C1 to C7) form the neck region of the spine. The first two vertebrae (atlas and axis) are different because they perform function not shared by the other cervical vertebrae. o Atlas – has no body, cervical one, the superior surfaces of its transverse processes contain large depression that receive occipital condyles of the skull. This joints allows you to nod “yes” o The axis – acts as the pivot for the rotation of the atlas and the skull. It has a large upright process which acts as the pivot joint. •

o The dense – is the joint between c1 and c2 allows you to rotate from side to side to indicate “No” o The c3 c3- c7 – is the “typical” cervical vertebrae. They are the smallest, lightest vertebrae, and most often their Spinous process are short. • Thoracic vertebra – the 12 thoracic vertebrae are typical. They are larger than the cervical vertebrae and are distinguishes by the fact that they are the only vertebrae to articulate with the ribs. The body is somewhat heart-shaped and has two costal facets on each side, which receive the heads of the ribs. The spinous process is long and hooks sharply downward, causing the vertebrae to look like a giraffe head view from the side. • Lumbar vertebrae – has the 5 lumbar vertebrae have massive, blocklike bodies. Their short hatchet- shaped spinous process make them look like a moose head from the lateral aspect. These are the sturdiest if the vertebrae because most of the stress on the vertebrae column occurs in the lumbar region. • Sacrum – is formed by the fusion of the 5 vertebrae. Superiorly it articulated with the L and inferiorly it connects with the coccyx. o Ala – wing-like that articulate laterally with the hip bones, forming the sacroiliac joints. o Median sacral crest – is the fused spinous process of the sacral vertebra. This flank laterally by the posterior sacral foramina. o Sacral canal – is the vertebral canal continuous inside the sacrum, and terminates in a large inferior opening call the sacral hiatus. • Coccyx - the tail bone. In visayan term “Kigol” Function of the vertebrae column • Support • Protect spinal cord • Movement Thoracic cage cage- the sternum, ribs and thoracic vertebrae make up the bony thorax. The bony

thorax is routinely called the thoracic cage because it forms a protective cone-shaped cage of slender bones around the organs of the thoracic cavity (heart, lungs and major blood vessels) Protects vital organs, 12 pairs of ribs; components of thoracic cage: • Sternum – breastbone, a typical flat bone and the result of the fusion of three bones, the manubrium, body or gladiolus, xiphoid process, it is attached to the seven parts of the ribs. • 3 important landmarks of sternum o Jugular notch or supersternal – is a concave upper border of the manubrium, it can be palpates easily, generally it is the level of the 3rd thoracic vertebrae. o Sternal angle – result where the manbrium and body meet at a slight angle to each other. Provides a handy reference point for counting ribs to locate the second intercostal space for listening to certain heart valves. o Xiphisternal joint – the point where the sternal body and xyphoid process fuse, lies at the level of the ninth thoracic vertebrae • The ribs – 12 ribs pairs form the walls of the bony thorax. (contrary to popular misconception, men do not have one rib fewer than women) all the ribs articulate with the vertebral column posteriorly and toward the anterior surface. o True ribs – attach directly to sternum by cartilage. Is the 1st to 7th ribs, attached directly to the sternum by costal cartilages. o False ribs – attach indirectly to sternum by cartilage. Is the nest five pairs, the 3 pairs attached indirectly to the sternum, the two pairs lack the sternal attachment, so they are also called the floating ribs. • Floating ribs – not attached to sternum

Appendicular Skeleton - After birth, bones are 271, after months some bones are fused, example; sacrum. - Is composed of 126 of the limbs and the pectoral girdle and pelvic girdle which attached the limbs to the axial skeleton Bones of the shoulder girdle or pectoral girdle - Clavicle or collar bone o Is a slender, doubly curve bone. o It attaches to the manubrium of the ...