Unit 2: The skeletal system (Bone tissue) Flashcards
1
Q
Describe what Bone is. What makes up the skeletal system?
A
Is an organ made up of several different tissue working together. The entire framework of bones and their cartilage constitutes the skeletal system.
2
Q
What is osteology?
A
The study of bone structure and the treatment of bone disorder is referred to as osteology.
3
Q
What are the six basic functions of the skeletal system?
A
- Support
- Protection
- Assistance in movements
- Mineral homeostasis (storage and releases)
- Triglyceride storage (yellow bone marrow)
- Bone cell production (red bone marrow)
4
Q
How does the skeletal system support the body?
A
It serves as the structural framework for the body by supporting soft tissues and providing attachment points for the tendons of most skeletal muscles.
5
Q
How does the skeletal system protect the body?
A
It protects the most important internal organs from injury.
6
Q
How does the skeletal system assists in movement?
A
Most skeletal muscles attach to bones, when they contract, they pull on bones to produce movements.
7
Q
How do bone tissues assist in mineral homeostasis?
A
Bone tissue stores several minerals like calcium and phosphorus, which contributes to the strength of bone. On demand, bone releases minerals into the blood to maintain critical mineral balances and to distribute the minerals to other parts of the body.
8
Q
How does bone tissue store triglycerides?
A
Yellow bone marrow consists mainly of adipose cells, which stores triglycerides. This stored fats are potential chemical energy reserve.
9
Q
How does blood tissue contribute in blood cell production?
A
In certain bones, red bone marrow produces RBCs, WBCs and platelets, a process called hemopoiesis. Red bone marrow consists of developing blood cells, adipocytes, fibroblasts, and microphages within a network of reticular fibers.
10
Q
Whats the difference between new born and adult bone marrow?
A
In newborns, all bone marrow is red and is involved in hemopoiesis, with increasing age, much of the bone marrow changes form red to yellow.
11
Q
What are the seven structures of the bone?
A
- Diaphysis
- Epiphyses
- Metaphysis
- Articular cartilage
- Periosteum
-Medullar cavity - Endosteum
12
Q
Define diaphysis.
A
The bones shaft or body. The long cylindrical main portion of the bone.
13
Q
Define Epiphyses.
A
The proximal and distal ends of the bone.
14
Q
Define Metaphyses.
A
The region between the diaphysis and epiphyses. In a growing bone, each metaphyses contains an epiphyseal (growth) plate. When the bone stops growing, the cartilage in the plate is replaced by bone; the resulting bony structure is known as epiphyseal line.
15
Q
Define what an epiphyseal (growth) plate is.
A
A layer of cartilage that allows the diaphysis of the bone to grow in length.
16
Q
Define articular cartilage.
A
A thin layer of hyaline cartilage covering the parts of the epiphysis where the bone forms an articulation (joints) with another bone. Articular cartilage reduces friction and absorbs shock freely. Articular cartilage lacks a perichondrium and blood vessels, repair damage is limited.
17
Q
Define periosteum. What is it composed of?
A
A tough connective tissue sheath and its associated blood supply that surrounds the bone surface wherever it is not covered by articular cartilage. Some periosteum also protects the bone, assists in fracture repair, helps nourish bone tissue, and serves as an attachment point for ligaments and tendons. Its composed of outer fibrous and osteogenic layer.
18
Q
What is periosteum attached to?
A
It is attached to underlying bone by perforating fibers, thick bundles of collagen that extends from the periosteum into the bone matrix.
19
Q
Define medullar cavity.
A
Also called marrow cavity. It is a hollow, cylindrical space within the diaphysis that contains fatty yellow bone marrow and numerous blood vessels in adults. This cavity minimizes the weight of the bone by reducing the dense bony material where it is least needed.
20
Q
Define endosteum.
A
A thin membrane that lines the medullar cavity. It contains a single layer of bone forming cell and a small amount of connective tissue.
21
Q
What is another name for bone and what does it contain?
A
Also called osseus tissue. Contains an abundant separated cells.
22
Q
Describe the process of calcification.
A
As mineral salts are deposited in the framework formed by the collagen fibers of the extracellular matrix, they crystallize and the tissue hardens. It is initiated by bone building cells called osteoblasts.
23
Q
What decides a bone hardness and flexibility?
A
A bones hardness depends on the crystallized inorganic mineral salts, a bones flexibility depends on its collagen fibers.
24
Q
What are the four types of cells present in bone tissue?
A
- Osteoprogenitor cells
- Osteoblasts
- Osteocytes
- Osteoclasts
25
Define Osteoprogenite cells.
Unspecialized bone stems cells derived from mesenchyme, they are precursor cells. These cells are the only bone cells to undergo cells division, developing into osteoblasts.
26
Define Osteoblasts.
Are bone building cells. They secrete collagen fibers and other organic components needed to build the extracellular matrix of bone tissue, they initiate calcification. Osteblasts surround themselves with the matrix, they become trapped and becomes osteocytes.
27
Define Osteocytes.
Mature bone cells, are the main cells in the bone tissue and maintain its daily metabolism. Osteocytes do not undergo cell division.
28
Define Osteoclasts.
These huge cells are concentrated in the endosteum. The cell releases powerful lysosomal enzymes and acids that digest the protein and mineral components of the underlying extracellular matrix. Osteoclasts help regulate blood calcium level.
29
Explain bone resorption.
The process by which the bones are absorbed and broken down by the body. The breakdown releases calcium and phosphorus into the blood stream. This breakdown occurs when the body has insufficient calcium.
30
Define compact bone tissue. What is is composed of?
The strongest form of bone tissue. Found beneath the periosteum of all bones and makes up the bulk of the diaphysis of long bones. It provides protection and support and resists the stresses produced by weight and movement. It is composed of repeating structural units called osteons.
31
Define concentric lamallae.
Circular plates of mineralized extracellular matrix of increasing diameter, surrounding a small network of blood vessels and nerves located in the canal. It's what makes up the osteons.
32
Define lacunae.
Between concentric lamallae are small spaces called lacunae. Which contains osteocytes.
33
Define canaliculi.
Radiating in all directions from the lacunae are tiny canaliculi, which are filled with extracellular fluid.
34
Define interstitial lamellae.
The area between neighbouring osteons contain lamellae called interstitial lamellae. They are fragments of older ostoens that have been partially destroyed during done rebuilding or growth.
35
Define circumferential lamellae.
Around the entire outer and inner circumference of the shaft of a long bone. The circumferential lamellae directly deep to the peritoneum are called external circumferential lamellae. They are connected to the periosteum by perforating fibers. The circumferential lamellae surrounding medullary cavity are called internal circumfernetial lamellae.
36
Define spongey bone tissue.
Also referred to as trabecular. These do not contain osteons. Spongy bone is always located in the interior of a bone, protected by compact bone.
37
where are bone marrow stored and where blood cells are produced?
Spongey bone in the hip, ribs, sternum, vertebrae, and proximal ends of the humerus and femur is the only site where bone marrow and blood cells are produced.
38
Define periosteal arteries.
Small arteries accompanied by nerves, enter the diaphysis and supply the periosteum and outer parts of the compact bone.
39
Where are the three places blood are carried away from?
- One or two nutrient veins accompany the nutrient artery and exit through the diaphysis.
- Numerous epiphyseal veins and metaphyseal veins accompany their respective arteries and exit through the epiphyses and metaphyses.
- Many small periosteal veins accompany their respective arteries and exit through the periosteum.
40
Differentiate between arteries and veins.
Arteries take blood in. Veins carry blood out.
41
What is the process of bone formation called?
The process by which bone forms is called ossification or osteogenesis.
42
When are the four situations bone formation occurs?
- The initial formation of bones in an embryo and fetus.
- The growth of bones during infancy, childhood, and adolescence until their adult sizes are reached.
- The remodelling of bone
- The repair of fractures throughout the life.
43
What is embryonic skeleton composed of?
the embryonic skeleton are initially composed of mesenchyme in the general shape of bones.
44
Define intramembranous ossification.
Bones forms directly within mesenchyme, which is arranged in sheetlike layers that resemble membranes. Its the simpler of the two methods of bone formation.
45
How does the soft spot of the fetal skull formed?
They undergo intramembranous ossification.
46
Define endochondral ossification.
Bone forms within hyaline cartilage that develop from mesenchyme.
47
What process does bone formation undergo?
Most bones are formed by endochondral ossification.
48
What are the steps of intramembranous ossification?
- Development of the ossification centre..
- Calcification.
- Formation of trabecular.
- Development of the periosteum.
49
What are the steps of endochondral ossification?
- Development of the cartilage model.
- Growth of the cartilage model.
- Development of the primary ossification centre.
- Development of the medullary (marrow) cavity.
- Development of the secondary ossification centres.
- Formation of the articular cartilage and the epiphyseal plate.
50
What are chondroblasts and what do they do?
The chondroblasts secrete cartilage extracellular matrix, producing a cartilage model consisting of articulate cartilage.
51
What covers the cartilage model?
Perichondrium.
52
How are chondrocytes formed?
Once chondroblasts become deeply buried in the cartilage extracellular matrix, they are called chondrocytes.
53
Differentiate between interstitial growth and appositional growth.
- Interstitial growth chondrocytes secrete new matrix within the cartilage and this causes it to grow in length. Within the tissue.
- Appositional growth occurs when chondroblasts secretes new matrix along existing surfaces and this causes the cartilage expand and widen. Outer surface of tissue.
54
Define primary ossification centre.
The first area of a bone to start ossifying.
55
Define secondary ossification centre.
Develops in the epiphyseal ends
56
What are the two major events in growing bones in length?
- Interstitial growth of cartilage on the epiphyseal side of the epiphyseal plate.
- Replacement of cartilage on the diaphysial side of the epiphyseal plate with bone by endochondral ossification.
57
What are the four zones in the growing bone?
- Zone of resting cartilage
- Zone of proliferating cartilage
- Zone of hypertrophic cartilage
- Zone of calcified cartilage
58
Define the zone of resting cartilage.
The term 'resting' is used because the cells do no function in bone growth. Rather, they anchor the epiphyseal plate to the epiphysis of the bone.
59
Define zone of proliferating cartilage.
These chondrocytes undergo interstitial growth as they divide and secrete extracellular matrix. The chondrocytes in this zone divide to replace the ones that died at the diaphysial side of the epiphyseal plate.
60
Define zone of hypertrophic cartilage.
This layer consists of large, maturing chondrocytes arranged in columns.
61
Define zone of calcified cartilage.
The final zone is only a few cell thick and consists mostly of chondrocytes that are dead because the extracellular matrix around them has calcified. Osteoclasts dissolve the calcified cartilage, and osteoblasts and capillaries from the diaphysis invade the area. Bone matrix replaces the calcified cartilage the 'new diaphysis/ that is firmly cemented to the rest of the diaphysis of the bone.
62
How does diaphysis increase in length and when does it stop?
The activity of the epiphyseal plate is the only way that the diaphysis can increase in length. When adolescence comes to an end, the epiphyseal plates close and the bone replaces all remaining cartilage.
63
Define epiphyseal line.
After the epiphyseal plate close during adolescence, it leaves a bony structure called the epiphyseal line, bone growth in length stops completely.
64
How do bone grow in thickness?
Bone can grow in thickness only by appositional growth.
65
Define remodelling of bone.
the ongoing replacement of old bone tissue by new bone tissue. It involves bone resorption and bone deposition.
66
Differentiate between bone resorption and bone deposition.
Bone resorption is the destruction of bone matrix.
Bone deposition is the formation of bone matrix.
67
What are the steps of bone resorption?
- During the process of bone resorption, an osteoclasts attaches tightly to the bone surface at the endosteum or periosteum and forms a leakproof seal at the edges of its borders.
- Then it releases protein digested lysosomal enzymes and acids into the sealed pockets.
- The enzymes digest collagen fibers and other organic substances while the acid dissolves the bone minerals.
- Working together, several osteoclasts carve out a small tunnel in the old bone.
- The degraded bone proteins and extracellular matrix minerals, enter the osteoclasts by endocytosis, cross the cell in vesicles, and undergo exocytosis.
- Now in the interstitial fluid, the product of bone resorption diffuse into nearby blood capillaries.
- Once a small area of bone has been resorbed, osteoclasts depart and osteoblasts move in to rebuild the bone in that area.
68
What are the three factors affecting bone growth and bone remodelling?
- Minerals
- Vitamins
- Hormones
69
Explain how minerals affect bone growth and bone remodelling.
Large amounts of calcium and phosphorus are needed while bones are growing. Also small amounts of magnesium , fluoride, and manganese. These minerals are also necessary during bone remodelling.
70
Explain how vitamins affect bone growth and bone remodelling.
Vitamin A stimulates activity of osteoblasts. Vitamin C is needed for synthesis of collagen, the main bone protein. Vitamin D helps build bones by increasing the absorption of calcium from foods in the gastrointestinal tract. Vitamin K and B12 are also needed for synthesis of bone proteins.
71
Explain how hormones affect bone growth and bone remodelling.
- Hormones most important to bone growth are the insulin like growth factors (IGF). IGFs stimulate osteoblasts, and promotes cell division, at the epiphyseal plate and in the periosteum, and enhances synthesis of the proteins needed to build new bone.
- Thyroid hormones also promote bone growth by stimulating osteoblasts.
- At puberty, the secretion of hormones known as sex hormones causes a dramatic effect on bone growth.
72
What are sex hormones?
The sex hormones includes estrogen (Produced by the ovaries) and androgens such as testosterone (Produced by the testes). These hormones are responsible for increased osteoblasts activity, synthesis of bone extracellular matrix, and the sudden 'growth spurt' that occurs. Sex hormones (especially estrogen) shuts down growth at the epiphyseal plate.
73
What is the bones role in calcium homeostasis?
Bone is the body's major calcium reservoir. One way to maintain the level of calcium in the blood is to control the rates of calcium resorption from bone into blood and of calcium deposition from blood to bone. Both nerve and muscle cells depends on the stable level of calcium ions to function properly. Small changes in the calcium ion concentration may be fatal.
74
How is calcium exchange regulated?
Calcium exchange is regulated by hormones, the most important of which is the parathyroid hormone (PTH). This hormone increases blood calcium levels.
75
How does the parathyroid hormone regulate calcium exchanged?
- PTH secretion functions via a negative feedback system.
- PTH also acts on the kidneys to decrease loss of calcium in the urine.
- PTH stimulates formation of calcitriol, this hormone promotes absorption of calcium from foods in the gastrointestinal tract in the blood. - When blood calcium rises above normal, the thyroid glands secrete calcitonin (CT).
- CT inhibits activity of osteoclasts, speeds blood calcium uptake by bone, and accelerate calcium deposition into bone.
76
How many named bones are there in an adult human skeleton?
206.
77
What is the main difference between adult human skeleton and infant human skeleton?
Human skeletons has 206 named bones, but infants have more bones, these bones fuse together later in life.
78
What are the two principal division of an adult skeleton?
Axial skeleton and appendicular skeleton.
79
What does the appendicular skeleton consists of?
Upper and lower limbs, plus the bones forming the girdles that connect the limbs to the axial skeleton.
80
What are the five types of bones?
- Long bones
- Short bones
- Flat bones
- Irregular bones
- Sesamoid bones.
81
Describe what long bones are.
Consists of a shaft and an epiphyses and are slightly curved for strength. Long bones mostly consists if compact bone tissue in their diaphyses but have considerable amount of spongy bone tissue in their epiphyses.
82
Where are long bones located?
- Femur (thigh bone)
- Tibia and fibula (leg bone)
- Humerus (arm bone)
- Ulna and radius (forearm)
- Phalanges (figners and toes)
83
Describe what short bones are.
Somewhat cube shaped. They consists of spongy bone except at the surface, which has a thin layer of compact bone.
84
Where are short bones located?
- Most carpal bones (wrist)
- Most tarsal bones (ankles)
85
Describe flat bones.
Generally thin and composed of two nearly parallel plates of compact bone tissue. Flat bones afford considerable protection and provide extensive area for muscle attachments.
86
Where are flat bones found?
- Cranial bones
- The sternum (chest bone)
- Ribs
- Scapulae (shoulder blades)
87
Describe what irregular bones are.
Have complex shapes and cannot be grouped into any other bone types. They vary in the amount of spongy and compact bone present.
88
Where are irregular bones found?
- Vertebrae (back bones)
- Hip bones
- Some facial bones
- Calcaneus (heel bone)
89
Describe what sesamoid bones are.
- Develops in certain tendons where there is considerable friction, tension and physical stress such as the palms and soles.
- They are not always completely ossified.
- Sesamoid bones protects tendons form excessive wear and tear, and they often change the direction of pull of a tendon.
90
What are sutural bones?
An additional type of bone classified by location rather than shape. They are small bones located in sutures (joint) between cranial bones.
91
What are surface markings?
Most are not present at birth but develop in response to certain forces and are not most prominent in the adult skeleton.
92
What are the two major types of surface markings? And describe them
Depressions and openings - allows the passage of soft tissues or form joints
Processes - projections or outgrowths that either helps form joints or serve as attachment points for connective tissue.
93
How many bones does the skull contain?
22 bones.
94
What are the two categories skull bones are grouped in?
- Cranial bones
- Facial bones
95
Describe what cranial bones are. What are the bones called?
- Encloses and protect the brain.
- There are 8 in total; the frontal, 2 parietal bones, 2 temporal ones, the occipital bone, the sphenoid and ethmoid bones.
96
Describe what facial bones are. What are the bones called?
There are 14 facial bone. 2 nasal bones, 2 maxilla, 2 zygomatic bone, and mandible, 2 lacrimal bones, 2 palatine bones, 2 inferior nasal conchae, and the vomer.
97
What other smaller cavities does the skull have?
- Nasal cavity
- Orbits (eye sockets)
- Paranasal sinuses
- Middle ear cavities
98
Describe what the frontal bones are.
Forms the forehead, and the roofs of the eye sockets. Soon after birth, the left and right sides of the frontal bone are united by the metopic sutures, which will usually disappear with age.
99
Describe what the parietal bones are.
The two parietal bones form the greater portion of the sides and roof of the cranial nerve. The internal surfaces of the parietal bones contain many protrusions and depressions that accomodate the blood vessels supplying the dura mater.
100
What is a temporal squama? And how is the zygomatic process related? And together what do the form?
The temporal squama are thin, flat part of the temple. Projecting from the inferior portion of the squama is the zygomatic process which articulates (forms a joint) with the temporal process of the zygomatic (cheek) bone. Together they form the zygomatic arch.
101
What makes up the tempomandibular joint (TMJ)?
A socket called the mandibular fossa articulates with the articular tubercle and forms the TMJ.
102
What forms the occipital bone?
Forms the posterior part and most of the base of the cranium.
103
Describe what a foramen magnum is.
Means large hole. The medulla oblongata connects with the spinal cord within this foramen, and the vertebral and spinal arteries also pass through it.
104
Describe what the occipital condyles are.
Oval processes with convex surfaces on either side of the foramen magnum.
105
Which joint allows us to nod our head 'yes'?
The atlanto-occipital joints.
106
Describe what the sphenoid bone is.
This bone is called the keystone of the cranial bones, because it articulates with all the other cranial bones which holds them together.
107
What is the space in the sphenoid bone called?
The sphenoidal sinus, which drains into the nasal cavity.
108
What are the bones in the axial skeleton?
- Skull
- Hyoid bone
- Auditory ossicles
- Vertebral column
- Thorax
109
What are the bones in the appendicular skeleton?
- Pectoral girdle
- Upper limbs
- Pelvic girdle
- Lower limbs
110
Describe what the mastoid bone is.
Contains mastoid air cells that communicate with the hollow space of the middle ear. Ear infections that spread to these cells cause mastoiditis.
111
Describe what the palatine process of maxilla is.
The union of the maxillary bones normally is completed before brith. If this fails, this forms a cleft palate.
112
Describe what the hypophyseal fossa is.
This fossa contains the pituitary gland.
113
Describe what the foramen rotundum is.
The maxillary branch of the trigeminal nerve pass through here.
114
Describe what the ethmoid bone is.
Forms part of the anterior portion of the cranial floor, the medial wall of the orbits, the superior portions of the nasal septum, and most of the side walls of the nasal cavity.
115
What is the nasal septum?
A partiton that divides the nasal cavity into right and left side.
116
Describe what the cribriform plate is.
It contains the olfactory foramina which the olfactory nerve pass through.
117
What is the mastoid process?
The point of attachment for several neck muscles.
118
What goes through the internal auditory meatus?
Facial nerves and vestibulacochlear nerve passes through here.
119
Describe what the petrous portion is.
This houses the internal and middle ear, which are the structures that are involved in hearing and equilibrium.
120
Describe what the nasal bones are.
They are paired and small, flattened, rectangular shaped bones that form the bridge of the nose. The major structural portion of the nose consists of cartilage.
121
Describe what the lacrimal bones are.
The paired lacrimal bones are thin and roughly resembles a fingernail in size and shape. These bones, the smallest bones of the face, are posterior and lateral to the nasal bones and for a part of the medial wall of each orbits.
122
What is a lacrimal fossa?
The lacrimal bones each contain a lacrimal fossa, that houses the lacrimal sac, a structure that gather tears and passes them into the nasal cavity.
123
Describe what the palatine bones are.
The two L shaped palatine bones form the posterior portion of the hard palate, part of the floor and lateral wall of the nasal cavity, and a small portion of the floors of the orbit.
124
Describe what the inferior nasal conchae are.
The two inferior nasal conchae are separate bones, and not part of the ethmoid bones. The nasal conchae increase the surface area of the nasal cavity and helps swirl and filter air before it passes into the lungs.
125
Which bone is involved in the sense of smell?
Only superior nasal conchae are involved in the sense of smell.
126
What is a vomer?
A roughly triangular bone on the floor of the nasal cavity that articulates superiorly with the perpendicular plate of the ethmoid bone and inferiorly with both the maxillae and palatine bones.
127
Describe what the maxillae is.
Unite to form the upper jaw bone. They articulate with every facial bone except for the mandible.
128
What is the hard palate?
The bony roof of the mouth, this separates the nasal cavity from the oral cavity.
129
Describe what the zygomatic bones are.
More commonly known as cheek bones. They articulate with the frontal, maxilla, sphenoid, and the temporal bones.
130
Describe what the mandible is.
Also called the lower part of the jaw. It is the largest, strongest facial bone. It is the only moveable skull bone (except for the auditory ossicles).
131
How many bones does the orbit consists of?
Seven bones.
132
Define foramina.
Openings for blood vessels, nerves, or ligaments.
133
Describe what sutures of the skull are. Describe the difference between adults and infants.
An immovable joint that holds most skull bones together. Sutures in the skulls of infants and children are moveable and functions as important growth centres in the developing skull.
134
What are the four most prominent sutures?
- Coronal sutures
- Sagittal suture
- Lambdoid sutures
- Squamous sutures
135
What does the coronal sutures unite?
They unite the frontal bones and both parietal bones.
136
What does the sagittal sutures unite?
Unites the two parietal bones on the superior midline of the skulls.
137
What does the lambdoid sutures unite?
Unites the two parietal bones to the occipital bone.
138
What does the squamous sutures unit?
these two sutures unite the parietal and temporal bones on the lateral aspects of the skull.
139
Describe what the paranasal sinuses.
They are cavities within certain cranial and facial bones near the nasal cavity. They are lined with mucous membranes that are continuose with the lining of the nasal cavity.
140
Describe what fontanels are.
At birth, bone ossification is incomplete, and the mesenchyme filled spaces become dense bone called fontanels, also called soft spots. Fontanels provide some flexibility to the fetal skull to go through the birth canal.
141
Describe what the hyoid bone is.
A single hyoid bone is a unique component of the axial skeleton because it does not articulate with any other bone. Rather it is suspended from the styloid process of the temporal bones by ligaments and muscles.
142
What does the hyoid bone support?
The hyoid bone supports the tongue, providing attachment sites for some tongue muscles and for the muscles of the neck and pharynx.
143
Describe what the vertebral column is. And its function.
It protects the spinal cord as well as supports the head and serves as a point of attachment for the ribs, pelvic girdle, and muscles of the back and upper limbs.
144
How many vertebrae do you have during early development? And what happens to them?
There are 33 vertebrae's and as the child grows, several vertebrae's in the sacral and coccygeal regions fuse.
145
How many vertebrae's does an adult skeleton have and were are they located?
There is a total of 26 vertebrae's;
- 7 cervical vertebrae (the neck region)
- 12 thoracic vertebrae (posterior to the thoracic cavity)
- 5 lumbar vertebrae (supporting the lower back)
- 1 coccyx (usually consists of four fused coccygeal vertebrae)
146
What is the main difference between the cervical, thoracic and lumbar vertebrae and the sacrum and coccyx vertebrae?
The cervical, thoracic, and lumbar vertebrae are moveable, sacrum and coccyx are not.
147
What do they mean by normal curves in a spine? Why does the spine have these curves?
The vertebral column is slightly bent in four parts.
The curves increase the strength of the column, and helps maintain balance in the upright position, absorbs shock during walking and help protect the vertebrae from fractures.
148
Differentiate between primary and secondary curves.
The thoracic and sacral curves are called primary curves because they retain the original curvature of the embryonic vertebral column. The cervical and lumbar curves are known as secondary curves because they begin to form later.
149
What are intervertebral discs?
Found between the bodies of adjacent vertebrae from the second cervical vertebrae to the sacrum. The discs form strong joints, permit various movements of the vertebral column, and absorbs vertical shock.
150
Differentiate between annulus fibrosus and nucleus pulposus.
Each intervertebral discs has an outer fibrous ring consisting of fibrocartilage called the annulus fibrosus and an inner soft, pulpy, highly elastic substance called nucleus pulposus. With age, the nucleus pulposus hardens and becomes less elastic.
151
What are the three parts of a typical vertebrae?
- Vertebral body
- Vertebral arch
- Processes
152
What is the vertebral body?
The thick disc shaped anterior portion is the weight bearing part of the vertebrae. Its superior and inferior surfaces are roughened for the attachment of cartilaginous intervertebral discs.
153
Describe what vertebral arch is.
A circle bone around the canal through which the spinal cord passes through.
154
Describe what the vertebral foramen is. What does it form?
Contains the spinal cord, adipose tissue, areolar connective tissue, and blood vessels collectively, the vertebral foramen of all vertebrae form the vertebral (spinal) canal.
155
Describe what the processes. How many are there?
Seven processes arise from the vertebral arch. A single spinous (spinal) processes projects posteriorly from the junction of the laminae. Three processes serve as points of attachment for muscles. The remaining four processes form the joints with the other vertebrae above and below.
156
What are the regions of the vertebral column?
- Cervical
- Thoracic
- Lumbar
- Sacral
- Coccygeal
157
Describe what the cervical vertebrae is.
The bodies of the cervical vertebrae are smaller than all other vertebrae except those that form the coccyx.
158
What are the three foramina of the cervical vertebrae?
- The vertebral foramina: the largest in the spinal column due to them housing the cervical enlargement of the spinal cord.
- Transverse foramen: where the vertebral artery, veins, and nerve fibers pass.
159
Differentiate between the altas (C1) and axis (C2).
- The atlas is the first cervical vertebrae inferior to the skull. Articulated with the occipital condyles of the occipital bone forms the atlanto-occipital joints.
- The second cervical vertebrae is the axis. Compared to the C1, C2 has a cervical body. The anterior arch of the atlas articulates with the dens of the axis which forms the atlanto-axial joint.
160
Define what the thoracic vertebrae is.
Considerably larger and stronger than cervical vertebrae. The spinous processes on T1 through to T10 are long, laterally flattened. The spinous processes on T11 and T12 are shorter, and broader. The articulations between the thoracic vertebrae and ribs are called vertebrocostal joints.
161
Define what the lumbar vertebrae are.
The largest and strongest of the unfused bones in the vertebral column. Their various projections are short and thick, the spinous processes are thick and broad, and are well adapted for the attachment of the large back muscles.
162
The moon is alone too, but somehow it still shines.
163
Define what the sacral and coccygeal vertebrae are.
The sacrum is a triangular bone formed by the union of five sacral vertebrae. The sacrum serves as a strong foundation for the pelvic girdle. The coccyx like the sacrum is triangular in shape. It is formed by the fusion of usually four coccygeal vertebrae.
164
What is the skeletal part of the thorax called? And what is it composed of?
Thoracic cage is a bony enclosure formed by the sternum, ribs, and their costal cartilages, and the body of the thoracic vertebrae. The costal cartilage attach the ribs to the sternum.
165
Describe what the sternum is. What are its parts?
Also called the breastbone. It is a flat, narrow bone located in the centre of the anterior thoracic wall and consists of three parts. The manubrium, the inferior, and the xiphoid process.
166
Describe what ribs are. How many are there?
Twelve pairs of ribs gives structural support to the sides of the thoracic cavity. The ribs increase in length from the first through to the seventh. Then decreases in length to through to the twelfth.
167
What is the function of the costal cartilages?
Contributes to the elasticity of the thoracic cage and prevent various blows to the chest from fracturing the sternum or ribs.
168
Differentiate between true ribs and false ribs.
The ribs that have costal cartilages and attach directly to the sternum are called true ribs. The remaining five pairs of ribs are termed false ribs because their costal cartilages either attach indirectly to the sternum or do no attach at all.
169
Define the function of the appendicular skeleton.
The primary function of the appendicular skeleton is movement.
170
Define what pectoral girdles are.
Also called shoulders.
171
What does the pectoral girdle consists of?
Clavicle and scapula.
172
What is the pectoral girdle attached to?
The pectoral girdles do not articulate with the vertebral column and are held in position and stabilized by a group of large muscles that extend from the vertebral column and ribs to the scapula.
173
Define what clavicles are.
Also called collarbone. It is rougher and more curved in males.
174
What are clavicles attached to?
The medial end called sternal end is rounded and articulate with the manubrium. The flat, lateral end, the acrominal end, articulate with the acromion.
175
Define what scapular is.
Also could shoulder blades. Articulates with the clavicle at the acromioclavicular joint and with the humerus at the glenohumeral joint (shoulder joint).
176
Define what the 'ridge of the spine' is in context with the scapular.
A prominent ride called the spine runs diagonally across the posterior surface of the scapula. The lateral end of the spine projects as a flattened, expanded process called the acromion.
177
How many bones are in the upper limb?
Each upper limb has 30 bones in three locations.
178
Define what the humerus is.
Also called arm bone, is the longest and largest bone of the upper limb. It articulates proximally with the scapula and distally with the two bones, and the ulna and the radius, to form the elbow joint.
179
What is the glenoid cavity?
The glenoid cavity of the scapula articulates with the head of the humerus to form the glenohumeral joint (shoulder joints).
180
What is unique about the surgical neck?
The surgical neck is where the majority of fractures often happen on the shoulder and humerus.
181
What is attached to the deltoid tuberosity?
Serves as a point of attachment for the tendons of the deltoid muscles.
182
What does the radial groove contain?
The radial nerve.
183
Differentiate between the coronoid fossa and the olecron fossa
The coronoid fossa receives the coronoid process of the ulna when the forearm is flexed. The olecron fossa receives the olecron process of the ulna when the forearm is extended.
184
How is the radial fossa related to the head of the radius?
The radial fossa articulates with the head when the forearm is flexed.
185
What is the function of the lateral and medial epicondyle?
Lateral and medial epicondyle is where tendons of most muscles of the forearm is attached.
186
Define what the ulna is.
Ulna is located on the medial aspects of the forearm and is longer than the radius. The ulna is connected with the pinky finger. The ulna is wide on the proximal end and it narrows at the distal end.
187
Define what the radius is.
The radius is the smaller bone of the forearm and is located on the lateral aspect of the forearm. The radius is connected with the thumb. The radius is narrow at its proximal end and widens at its distal end.
188
What is attached to the styloid process?
The styloid process provides attachment for the brachioradialis muscle and for the attachment of the radial collateral ligament to the wrist.
189
Where does the ulna and radius articulates with?
At the elbow joint.
190
What are the three sites the ulna and the radius connect to?
- A broad, flat, fibrous connective tissues called the interosseous membrane joints the shaft of the two bones.
- The ulna and radius articulates directly at their proximal and distal end.
- The distal end of the radius articulates with three bones of the wrist to form the radiocarpal joint.
191
What are the three skeletons of the hands?
Carpals, metacarpals, and phalanges.
192
What is the wrist called and what does it compose of?
The carpus consists of eight small bones called the carpals, joined together by ligaments.
193
What articulates the carpal bones?
Articulations among carpal bones are called intercarpal joints.
194
What are the bones in the proximal row of the carpals?
- Scaphoid
- Lunate
- Triquetrum
- Pisiform.
(LI(T)PS?)
195
What are the bones in the distal row of the carpals?
- Trapezium
- Trapezoid
- Capitate
- Hamate
(HA(C)TT?)
196
What is unique with scaphoid and the capitate?
The scaphoid bone is whats mostly broken when injured, the capitate is the largest carpal bones.
197
Where is the elbow joint formed by?
- The trochlear notch of the ulna with the trochlea of the humerus.
- The head of the radius with the capitulum of the humerus.
198
What is the palm called and what does it consists of?
The metacarpus consists of five bones called metacarpals.
199
What does each metacarpals consists of? And where does it articulate with?
Proximal base, an intermediate shaft, and the distal head. The bases articulates with the distal row of carpal bones to form the carpometacarpal joint. The heads of the metacarpals are commonly called knuckles.
200
What are the bones of the digits called and what does it consists of?
The phalanges makes up the distal part of the hand. There are 14 phalanges in the 5 digits of each hands.
201
What does each phalange consists of?
The thumb has two phalanges called proximal and distal phalanges. The other four has three, proximal, middle and distal. Joints between phalanges are called interphalangeal joints.
202
What is the pelvic girdle?
Also called the hips. Consists of two hip bones or pelvic bone. Thr hip bones unite anteriorly at a joint called the pubic symphysis.
203
What creates the bony pelvis? What is its function?
The complete rings composed of the hip bones, pubic symphysis, sacrum, and coccyx forms a deep basin like structure called the bony pelvis.
The bony pelvis provides a strong and stable support for the vertebral column and pelvic and lower abdominal organs.
204
Define what the ilium is.
The largest of the three hip components, composed of a superior ala and an inferior body.
205
Define what the ischium is.
The inferior, posterior portion of the hip bones, comprises a superior body and an inferior ramus.
206
What is the obturator foramen?
The largest foramen in the skeleton.
207
Define what the pubis is.
Also called the pubic bone. Lateral end of the pubic crest is a projection called the pubic tubercle.
208
Define what the pubis symphysis is.
Is the joint between the two pubes of the hip bones. these joints weaken and become flexible late in the pregnancy. It consists of disc of fibrocartilage.
209
Define what the acetabulum is and what goes in it.
The acetabulum is a deep fossa formed by the ilium, ischium and the pubis. The socket accepts the rounded head of the femur.
210
Differentiate between the true and false pelvis.
The portion of the bony pelvis superior to the pelvic bring is referred to as the False (greater) pelvis. The space enclosed by the false pelvis is part of the lower abdomen.
The portion of the bony pelvis inferior to the pelvic brim is the true (lesser) pelvis.
211
What does the true pelvis contain?
The lesser pelvis contain an inlet, an outlet, and a cavity.
212
What is a pelvic brim?
The bony pelvis is divided into superior and inferior portions by boundary called the pelvic brim the forms the inlet into the pelvic cavity from the abdomen.
213
What is the pelvic axis?
Is an imaginary line that curves through the true pelvis. During childbirth the axis is the route taken by the babys head.
214
Differentiate between male and female pelves.
Bones of the males are larger and heavier and possesses a larger surface markings than females.
Most of the structural differences in the pelves are adaptation to the requirement of pregnancy and childbirth.
215
How many bones are there in the lower limb?
Each lower limb has 30 bones in four locations.
216
What are the two skeleton of the thigh?
The femur and the patella.
217
Define what the femur is.
Also called the thigh bone, it is the longest, heaviest, and strongest bone in the body. Its proximal end articulates with the acetabulum of the hip bone. Its distal end articulates with the tibia and patella.
218
Where is hip fractures usually located?
A broken hip is more often associated with a fracture in the neck of the femur.
219
Define what the greater and lesser trochanter are.
The greater trochanter and the lesser trochanter are projections from the junctions of the neck and shaft that serve as points of attachments for the tendons of some of the thigh and buttock muscles.
220
What is the kneecap called?
The patella is a small, triangular bone.
221
What are the two skeleton of the leg?
Tibia and fibula.
222
Define what tibia is.
Also called the shin bone. Is the largest weight bearing bone of the leg. The tibia articulates at its proximal end with the femur and at the distal end with the fibula.
223
Which long bone in the body gets fractured more often?
The tibia, also the most frequent site of an open (compound) fracture.
224
Define what the fibula is.
The fibula is considerably smaller. The fibular does not articulate with the femur, but it does help stabilize the ankle joints.
225
Where does the sciatic nerve pass through?
The greater sciatic notch.
226
What is attached to the gluteal tuberosity and linea aspera?
Both ridges serve as attachment points for the tendons of several thigh muscles.
227
Define what the fovea capitis is.
It connects the femur to the acetabulum.
228
Define what the tibial tuberosity is.
Points of attachment for the patellar ligament.
229
What are the three bones of the foot?
Tarsals, metatarsals, and phalanges.
230
What is the ankle called? And what does it consists of?
The tarsal is the proximal region of the foot and consists of seven tarsal bones.
- Talus
- Calcaneus
- Navicular
- Cuneiform bones. (3)
- Cuboid
(3Cs TN)
231
What is the strongest and largest tarsal bone?
The calcaneus.
232
What does the metatarsus consists of?
It consists of five metatarsal bones. The first metatarsal is thicker than the others because it bears more weight.
233
What does the phalanges of the feet consists of?
The distal components are similar to the phalanges of the hands. the great or big toe has two lrage, heavy phalanges.
234
Define what the arches of the foot is.
The bones of the foot are arranged in two arches that are held in position by ligaments and tendons.
235
Differentiate between longitudinal arch and transverse arch.
The longitudinal arch has two parts. The medial and lateral part originates at the calcaneus.
The transverse arch is found between the medial and lateral aspects of the foot.
236
Define joints. What is the study of joints called?
Flexible connective tissue hold bones together at points of contact called joints while still permitting, in most cases, some degree of movement.
Arthrology.
237
What is another name for joints?
Articulations or arthrosis.
238
What are the two structural classifications of joints?
- The presence or absence of a space between the articulating bones called a synovial cavity.
- The type of connective tissue that binds the bones together.
239
What are the three types of joints?
- Fibrous joints: No synovial cavity and the bones are held together by dense irregular connective tissue that is rich in collagen fibers.
- Cartilaginous joints: No synovial cavity and the bones are held together by cartilage.
- Synovial joints: The bones forming the joints have a synovial cavity and are united by the dense irregular connective tissue of an articular capsule and often by accessory ligaments.
240
What are the three functional classifications of joints?
- Synarthrosis: An immovable joint.
- Ampiarthrosis: A slightly moveable joint.
- Diarthrosis: A freely moveable joint. All diarthrosis are synovial joints. They have a variety of shapes and permit several different types of movements.
241
What are the three types of fibrous joints?
- Sutures
- Syndesmoses
- Interosseous membrane
242
Define sutures in fibrous joints?
Composed of a thin layer of dense irregular connective tissue; sutures only occur between bones of the skull.
In older individuals, sutures are immovable (synathrosis), and in infants and children, they are slightly moveable (ampiarthrosis).
243
What are synostosis?
Sutures that are replaced by bones in the adults. Eventually, sutures become obscure as you age.
244
Define syndesmoses.
A fibrous joint in which there is more distance between the articulating surfaces and more dense irregular connective tissue than in a suture. It permits slight movement (amphiathrosis).
245
Define interosseous membraner.
A substantial sheet of dense irregular connective tissue that binds neighbouring long bones and permits slight movements (ampiarthrosis).
246
What are the two principal interosseous membrane joints?
- Occurs between the ulna in the forearm.
- Occurs between the tibia and fibula in the leg.
247
What are the three types of cartilaginous joints?
- Synchondroses
- Symphyses
- Epiphyseal cartilage
248
Define synchondroses joints.
A cartilaginous joint in which the connecting material is hyaline cartilage and is slightly moveable.
249
Define symphyses.
A cartilaginous joint in which the ends of the articulating bones are covered in hyaline cartilage, but a broad, flat, disc of fibrocartilage connects the bones. Symphyses are slightly moveable.
250
Explain what epiphyseal cartilage is.
Are actually hyaline cartilage growth centres during endochondral bone formation, not joints associated with movements. It is immoveable.
251
Explain what a synovial joint is.
The unique characteristics of a synovial joint is the presence of a space called a synovial cavity or joint cavity, between the articulating joints.
Synovial joints are considered freely moveable (diarthroses).
252
Define articular cartilage.
The bones at a synovial joints are covered by a layer of hyaline cartilage called articular cartilage. Articular cartilage reduces friction between bones in the joints.
253
Explain what articular capsule is.
A sleeve like articular cartilage or joint capsule, that surrounds the synovial joint and encloses the synovial cavity and unties the articular bones.
254
What are the two cavities of the articular capsule?
- Fibrous membrane: usually consists of dense irregular connective tissue that attaches to the periosteum of the articulating bones. They are flexible and has great tensile strength.
- Synovial membrane: composed of areolar connective tissue with elastic fibers. At many synovial joints the synovial membrane includes accumulation of adipose tissue called articular fat pads.
255
Define ligaments.
Fibrous membranes are flexible and has great tensile strength. The strength of these fiber bundles, called ligaments, is one of the principal mechanical factors that hold bones close together in a synovial joint.
256
Explain synovial fluid.
The synovial membrane secreted synovial fluid, a viscous, clear or pale yellow fluid. It forms a thin film over the surfaces within the articular capsule.
Its functions include reducing friction by lubricating the joints, absorbing shock, and supply oxygen and nutrients and remove CO2.
Synovial fluids also contains phagocytic cells.
257
Differentiate between extracapsular ligaments and intracapsular ligaments.
Many synovial joints also contain accessory ligaments called extracapsular ligaments which lies outside the articular capsule, and intracapsular ligaments which occurs within the articular capsule, but are excluded from the synovial cavity.
258
What are articular discs?
Also called menisci. They inside some synovial joints, pads of fibrocartilage lie between the articular surfaces of the bones.
259
What are the five known functions of the articular discs?
- Shock absorption
- Providing a better fit between articulating bony surface
- Providing adaptable surface of combined movements
- Weight distribution
- Distribution of synovial lubricant across the articular surface of the joints.
260
Define labrum.
Prominent in the ball and socket joints of the shoulder and hip. It is the fibrocartilaginous lip that extends from the edge of the joint socket.
261
What supplies the joints and cartilage?
The nerves that supply a joint are the same as those that supply the skeleton muscles that move the joints. The chondrocytes in the articular cartilage of a synovial joints receive oxygen and nutrients from synovial fluids derived from blood; all other joint tissues are supplied directly by capillaries.
262
Explain what bursae is.
Sac like structures call bursae are strategically situated to alleviate friction in some joints. They are filled with a small amount of fluid that is similar to synovial fluids. the sacs cushion the movement of these body parts against one another.
263
Explain what tendon sheaths are.
Tendon sheaths also reduce friction in joints.
These sheaths wrap around certain tendons that experience considerable friction as they pass through tunnels formed by connective tissue and bones.
264
Explain the two layers of the tendon sheath.
The inner layer is called visceral layer, they are attached to the surface of the tendon. The outer layer is called parietal layer, is attached to bone.
265
Explain gliding in the context of synovial joints.
A simple movement in which nearly flat bone surfaces move back and forth and from side to side.
266
Explain what the angular movements are.
There is an increase or a decrease in the angle between articulating bones.
- Flexion, extension, lateral flexion, hyperextension.
- Abduction, adduction, and circomduction.
267
Explain what flexion, extension, lateral flexion, and hyperextension are.
- Flexion and extension are opposite movements.
- The movement of the trunk sideways to the right or left is called lateral flexion.
- Continuation of extension beyond the anatomical position is called hyperextension.
268
Explain what abduction, adduction, and circomduction.
- Abduction, also called radial deviation, is the movement of a bone away from the midline.
- Adduction, also called ulnar deviation, is the movements of a bone towards the midline.
- Circumduction is the movement of the distal end of a body part in a circle.
269
Explain what rotation is.
A bone revolves around its own longitudinal axis.
270
Differentiate between medial (internal) rotation and lateral (external) rotation.
If the anterior surface of a bone of the limb is turned towards the midline, the movement is medial rotation.
If the anterior surface of the bone of a limb is turned away from the midline, the movement is called lateral rotation.
271
What are the 11 special movements in joints?
Occurs only at certain joints;
- Elevation: a superior movement of a body part such as closing the mouth.
- Depression: an inferior movement of a body part such as opening the mouth
- Protraction: a movement of a body part anteriorly like thrusting your jaw forwards.
- Retraction: a movement of a protracted part of the body back to the anatomical position like bringing your jaw back from thrusting.
- Inversion: a movement of the sole medially at the interstitial joints.
- Eversion: a movement of the sole laterally at the intertarsal joints.
- Dorsiflexion: Refers to bending of the foot at the ankle. It occurs when your standing on your heel.
- Plantar flexion: involves bending of the foot at the ankle joint in the direction of the plantar or inferior surface. Like standing on your toes.
- Supination: a movement of the forearm at the proximal and distal radioulnar joints where the palm is turned anteriorly.
- Pronation: a movement of the forearm at the proximal and distal radioulnar joints where the palm is turned posteriorly.
- Opposition: the movements of the thumb at the carpometacarpal join in which the thumb moves across the palm to touch the tips of the finger.
272
What are the six types of synovial joints?
- Plane joints
- Hinge joints
- Pivot joints
- Condyloid joints
- Saddle joints
- Ball and socket joints
273
Explain what plane joints are.
Also called planar joints, they are flat or slightly curved. They primarily permit back and forth, side to side movements, but may also rotate.
Many plane joints are biaxial, meaning they rotate in addition to sliding.
They are also triaxial, permitting movement in three axes.
274
Describe what hinge joints are.
The convex surface of one bone fits into the concave surface of another bone. Hinge joints produce an angular, opening and closing motion like that of a hinged door. They are also uniaxial, because they typically allow motion around a single axis.
Hinge joints only permit flexion and extension.
275
Describe what pivot joints are.
Also called trochoid joints. When the rounded or pointed surface of one bone articulate with a ring formed partly by another bone and partly by ligaments.
Pivot joints are uniaxial because it allows rotation only around its own axis.
276
Describe what condyloid joints are.
Also called ellipsoidal joint. The convex oval shaped projection of one bone fits into the oval shaped depression of another bone. They are biaxial because they move around two axis.
277
Describe what saddle joints are.
Also called sellar joints. The articular surface of one bone is saddle shaped, and the articular surface of the other bone fits into the 'saddle'. Saddle joints are biaxial.
278
Describe what ball and socket joints are.
Also called sphenoid joints. consists of the ball like surface of one bone fitting into a cup like depression of another bone. These joints are triaxial, permitting movements around three axes.
279
What is unique about the temporomandibular joint (TMJ)?
The TMJ is the only freely movable joint between skull bones. Only the mandible moves.
280
Explain what shoulder joints are.
A ball and socket joint formed by the head of the humerus and the glenoid cavity of the scapula. Also called humeroscapular or glenohumeral joint.
281
What kind of synovial joints are the hip joints?
A ball and socket joint formed by the head of the femur and the acetabulum of the hip bones.
282
What are the two anatomical components of the hip joints?
- Articular capsule
- Ligaments of the head of the femur.
283
What is the study of muscles called?
Myology
284
Describe what skeletal muscle tissues are.
They move the bones of the skeleton. They are striated and are mainly voluntary. Most skeletal muscles also are controlled subconsciously like your diaphragm.
285
Describe what the cardiac muscle tissue is.
Only the heart contains the cardiac muscle tissue, which forms most of the heart wall, cardiac muscle is also striated but its action is involuntary.
The heart beats because it has its own natural pace maker that initiate each contraction. This built in rhythm is termed autorythmicity.
286
Describe what smooth muscle tissue is.
Located in the walls of hollow internal structures, such as blood vessels, airways, and most organs in the abdominopelvic cavity. Smooth muscle are non-striated.
Smooth muscles are usually involuntary and some smooth muscles has autorythmicity.
287
What regulates the cardiac and smooth muscles?
Both cardiac and smooth muscles are regulated by neurons that are a part of the autonomic division of the nervous system.
288
What are the four functions of muscle tissues?
- Producing body movements
- Stabilizing body positions
- Storing and moving substances within the body
- Generating heat
289
What are the three properties of muscle tissue?
- Electrical excitability: A property of both muscles and nerve cells is the ability to respond to certain stimuli by producing electrical signals called action potential.
- Contractility: The ability of muscle tissue to contract forcefully when stimulated by an action potential.
- Extensibility: The ability of muscular tissue to stretch, within limits, without being damaged.
- Elasticity: The ability of muscular tissue to return to tis original length and shape after contractility of extension.
290
For muscles cells, what are the two main types of stimuli that trigger muscle action potential?
- Auto rhythmic electrical signals
- Chemical stimuli
291
Explain what fascia is.
It is a dense layer or broad band of irregular connective tissue. Fascia allows free movement of muscles; carries nerves, blood vessels, and lymphatic vessels; and fills spaces between muscles.
292
What are the three layers of connective tissue extends from the fascia to protect and strengthen skeletal muscles? What are its functions?
- Epimysium
- Perimysium
- Endomysium
They are continues with the connective tissue that attaches skeletal muscle to other structures such as bones or other muscles.
293
What is the sarcolemma and how is the transverse tubules related?
The sarcolemma is the plasma membrane of a muscle cell. Thousands of tiny invaginations of the sarcolemma, called transverse tubules, tunnels in from the surface toward the centre of each muscle fibers.
Muscle action potentials travel along the sarcolemma and through the T tubules, quickly spreading out to the muscle fibers.
294
Explain what the sarcoplasm is.
Within the sarcolemma is the sarcoplasm, the cytoplasm of a muscle fiber. Sarcoplasm includes a substantial amount of glycogen. It also contains a red coloured protein called myoglobin. This protein found only in muscle, binds oxygen molecules that diffuse into muscle fibers from interstitial fluid.
295
How are the sarcoplasm and myofibrils related?
The sarcoplasm appears stuffed with the little thread called myofibrils. Myofibrils prominent striations make the entire skeletal fiber appear stripped. A fluid filled system of membranous sacs called the sarcoplasm reticulum encircles each myofibril.
296
What is the terminal cistern? What forms the triad?
Dilated end sacs of the sarcoplasmic reticulum called terminal cisterns butt against the T tubules from both sides. x1 transverse tubules with x2 terminal cisterns make up the triad.
297
What element triggers a muscle contraction?
Release of calcium ions triggers muscle contractions.
298
Explain how the filaments and the sarcomere are related.
Within the myofibrils are smaller protein structures called filaments (myofilaments). The filaments are arranged in compartments called sarcomere which are the basic functional unit of a myofibril.
299
Differentiate between thin and thick filaments.
Thin filaments are composed of the protein actin.
Thick filaments are composed of the protein myosin.
300
Describe the function of the Z discs.
Narrow, plate shaped regions of dense protein material called Z discs separate one sarcomere to the next.
301
What is the main difference between the I band and the H zone?
The I band is a lighter, less tense area that contains thin filaments and NOT thick filaments.
The H zone contains thick filaments but NOT thin filaments.
302
What are the three kinds of proteins that myofibrils are built form? What do they consists of?
- Contractile proteins: Myosin and actin
- Regulatory proteins: Tropomyosin and troponin
- Structural proteins: Titan
303
Explain what the protein myosin do.
Myosin is the main component of thick filaments and function as a motor protein.
There is the myosin tail which points towards the M line. The two projections of each myosin molecule are called myosin heads.
304
What are the two binding sites of the protein myosin?
- Actin binding site
- ATP binding site
305
Explain what the protein actin do.
The main component of the thin filament is actin. On each actin molecule is a myosin binding site, where a myosin head can attach.
306
Explain what tropomyosin and troponin do.
The tropomyosin strands are held in place by troponin molecules. When calcium ions bind with troponin, troponin undergoes a conformational change, this change moves tropomyosin away from myosin-binding sites on actin.
307
Explain what the protein titan do.
Titan is the third most plentiful protein in skeletal muscle. It helps stabilize the position of the thick filaments.
308
How is the contraction cycle triggered?
On the onset of contraction, the sarcoplasmic reticulum releases calcium ions into the sarcoplasm. There, they bind to troponin. Troponin then moves tropomyosin away from the myosin-binding sites on actin. Once the binding sites are 'free', the contraction cycle begins.
309
Explain how the contraction cycle work.
- ATP hydrolysis: The energy generated from the hydrolysis reaction is stored in the myosin head for later use. The myosin is energized when it contains stored energy. It properly aligns itself perpendicular to the actin molecule.
- Attachment of myosin to actin: The energized myosin head attaches to the myosin binding site on the actin and releases hydrolyzed phosphate group, this is referred to cross bridge. Only one head of the myosin binds to the actin at a time.
- Power stroke: After the bridge is formed, the myosin head pivots, changing positions. As it changes, it pulls the thin filament past the thick filament towards the centre of the sarcomere, generating tension in the process. Once the power stroke occurs, ADP is released form the myosin head.
- Detachment of myosin from actin: At the end of the power stroke, the cross bridge remains firmly attached to actin until it binds another molecule of ATP. As ATP binds to the ATP binding site on the myosin head, the myosin head detaches form actin.
310
Explain what excitation contraction coupling is.
It is the sequence of events that links excitation (a muscle action potential) to contraction (sliding of the filaments).
311
What neurons stimulate skeletal muscle fibers to contract? Where does it arise?
Somatic motor neurons. Muscle action potential arise at the neuromuscular junction.
312
Explain what the neuromuscular junction is.
The synapse between a somatic motor neuron and a skeletal muscle fibers.
313
Differentiate between a synapse and the synaptic cleft.
At most synapses, a small gap called synaptic cleft seperated the two cells. A synapse is a region where communication occurs between two neurons, or between a neuron and a target cell.
314
How do cells communicate?
Cells do not physically touch, they communicate by releasing a chemical messenger called neurotransmitters.
315
What are the three ways the muscle fibers produce ATP?
- Creatinine phosphate: The first source of energy when muscle contraction begins.
- Anaerobic glycolysis: Produces two ATPs, but are faster.
- Aerobic respirations: Makes 30-32 ATP, an is slower.
316
What are the two sources of oxygen when muscle tissue needs it?
- Oxygen that diffuse into muscle fibers from the blood.
- Oxygen released by myoglobin within muscle fibers.
317
How badly do you want it?
318
Explain what muscle fatigue is.
The inability of a muscle to maintain force of contraction after prolonged activity. It mainly results from changes within muscle fibers. The response of tiredness and the desire to stop activity before muscle fatigue is called central fatigue.
319
What are thought to contribute to muscle fatigue?
- Protective mechanism to stop a person from exercising before muscles get damaged.
- Inadequate release of calcium ions from the SR, resulting in the decline of calcium concentration in the sarcoplasm.
- Depletion of creatinine phosphate also is associated with fatigue, but the ATP levels in fatigue muscles often are not much lower than a resting muscle.
- Insufficient oxygen
- Depletion of glycogen/nutrition
- Build up of lactic acid and ADP
- Failure of actin potentials in the motor neuron to release enough acetylcholine.
320
Explain what oxygen debt is.
Used to refer to the added oxygen, over and above the resting oxygen consumption, that is taken into the body after exercise.
321
What is the oxygen debt used for in the body?
- To convert lactic acid back into glycogen stores in the liver.
- To resynthesizes creatine phosphate and aTP in muscle fibers.
- To replace the oxygen removed from myoglobin.
322
Explain what a motor unit is and how the motor unit recruitment work.
A single somatic neuron makes contact with an average of 150 skeletal muscle fibers, all of the muscle fibers in one unit contract in unison.
Motor unit recruitment is the process by which different motor units are activated to produce a given level and types of muscle contraction.
323
Explain what myogram is. What are its phases?
A myogram is a record of a muscle contraction.
- Latent period: The delay in between the application of the stimulus. It stimulates more calcium ions to be release.
- Contraction period: The calcium ions binds to troponin, and cross bridge is formed.
- Relaxation period: Actively transported back into the sarcoplasmic reticulum, myosin binding sites are covered by tropomyosin.
324
Explain what the wave summation is.
When a second stimulus occurs after the refractory period of the first stimulus is over, the second contraction will actually be stronger. Stimuli arriving at the different times cause larger contraction is called wave summation.
325
Differentiate between unfused (incomplete) tetanus and fused (complete) tetanus.
When a skeletal muscle fiber is stimulated and can only partially relax between stimuli, the result is a sustained but wavering contraction called unfused tatanus.
When a muscle fiber is stimulated and it does not relax at all, the result is fused tetanus.
326
Differentiate between isotonic and isometric concentrations.
In an isotonic contraction, the tension developed in the muscle remains almost constant while the muscle changes its length. Isotonic contractions are used for body movements and for moving parts.
In an isometric contraction, the tension generated is not enough to exceed the resistance of an object, and the muscle does not change its length. These contractions are important for maintaining posture. These are not for movement.
327
Describe the two types of isotonic contractions.
- Concentric isotonic contraction: is great enough to overcome the resistance of the object to be moved, the muscle shortens and pulls on another structure, such as a tendon.
- Eccentric isotonic contraction: when the length of a muscle increases during a contraction. Repeated eccentric contractions (walking) produce more muscle damage and more delayed onset muscle soreness than concentric contraction.
328
Differentiate between red muscle fibers and white muscle fibers.
Skeletal muscle fibers that have a high myoglobin content are termed red muscle fibers and appear darker. Red muscle fibers contain more mitochondria.
Those that have a low content of myoglobin are called white muscle fibers and appear lighter.
329
What are the three muscle fibers classification?
- Slow oxidative fibers: they contain large amounts of myoglobin and many blood capillaries. These fibers generate ATP mainly by aerobic respirations. These fibers are slow
- Fast oxidative glycolytic fibers: The largest fibers. Also have larger amounts of myoglobin and blood capillaries. Also through aerobic respiration. These fibers are fast.
- Fast glycolytic fibers: Low myoglobin content, fewer blood capillaries, and fewer mitochondria and also appear white. Generates ATP by glycolysis. They are fast but tire easily.
330
How is cardiac muscles unique?
Cardiac muscle tissues have similar arrangement with the skeletal muscle fibers but they contain intercalated discs. These discs are unique just to cardiac muscles. These discs connects the cardiac muscles together.
331
Explain what intercalated discs are.
The discs contains desmosomes, which hold the fibers together, and gap junctions allows muscle action potentials to spread from one cardiac muscle fibers to another.
332
Differentiate between visceral (single unit) smooth muscle tissue and multi unit smooth muscle tissues.
Smooth muscle tissue is usually activated involuntary of the two types, the most common is visceral smooth muscle tissue. They are auto rhythmic. This stimulates many adjacent fibers to contract.
Multi unit smooth muscle tissue consists of individual fibers, each with its on motor neuron terminal and few gap junctions. This only contract that specific fiber.
333
How does muscle tissue regenerate itself?
Mature skeletal muscle fibers have lost the ability to undergo cell division, growth of skeletal muscle fibers after birth is mainly due to hypertrophy.
New smooth muscle fibers can arise from cells called periocytes.
334
Describe what hypertrophy, hyperplasia and periocytes are.
- Hypertrophy: the enlargement of existing cells
- Hyperplasia: an increase in the number of fibers
- Periocytes: stem cells
335
How many bones form each orbit? Which ones are they?
Seven bones.
- Three cranial bones: frontal, sphenoid, and ethmoid
- Four facial bones: palatine, zygomatic, lacrimal, and maxilla
