A&P EXAM II
CHAPTER 5-THE INTEGUMENTARY SYSTEM
I. THE INTEGUMENTARY SYSTEM-includes the skin and its derivatives (hair, nails and glands). The
skin accounts for about 7% of our total body weight and varies in thickness throughout the body.
A. Dermatology-area of science that focuses on the diagnosis and treatment of skin
disorders.
II. FUNCTIONS OF THE SKIN:
A. Protection-Resistance to Trauma and Infection
1. Provides a physical barrier to prevent bacterial and viral invasion of the body.
2. Provides chemical protection by secreting melanin and natural antibiotics (like
dermcidin and defensin).
3. Provides biological protection by producing cells (like Langerhan’s cells) that are
involved in immune responses.
B. Regulation of Body Temperature (Thermoregulation)
1. Can occur via sweat production when the body is too hot.
2. In cold conditions, blood can be removed from the skin, thus reducing heat loss at
the surface of the body.
C. Cutaneous Sensation
1. Cutaneous Sensory Receptors-are located throughout the skin. These are actually
a part of the Nervous System and they function by detecting and responding to
stimuli on the surface of the skin and stimuli external to the skin.
D. Vitamin D Production-this begins when UV light strikes special molecules in the skin.
This molecule travels to the kidneys and liver where it is converted into the active form of
Vitamin D (Calcitrol).
E. Blood Reservoir-the skin can store large supplies of blood.
F. Immunity
G. Excretion-of waste materials via sweat production. Sweat is composed of salts and
ammonia.
H. Absorption-of the fat-soluble vitamins (A, D, E, K).
III. The skin is composed of two distinct layers: the epidermis and the dermis.
IV. THE EPIDERMIS-the outer layer of the skin. Is composed of keratinized stratified squamous
epithelial tissue.
A. 4 Types of Cells in the Epidermis:
1. Melanocytes-synthesize and store melanin. Are found in the deepest layers of the
skin.
a. Melanin is stored in special storage structures called melanosomes.
b. Melanosomes accumulate on the sunny side of keratinocytes to protect
them from UV light.
2. Keratinocytes-produce the protein keratin which forms a protective layer over the
skin.
a. These are the most numerous types of cells in the epidermis. Millions of
these rub off the skin every day. We replace our epidermis every 25-45
days.
b. These cells are dead at maturity.
c. These cells store keratohyalin, the precursor molecule to keratin.
3. Langerhan’s Cells-arise from bone marrow and migrate to the epidermis. These act
as macrophages that help to activate our immune system. These are easily
damaged by UV light. These are also referred to as Dendritic Cells.
4. Merkel Cells-are located deep in the epidermis and are involved in detecting tactile
(touch) stimuli.
a. These tend to be more common in areas of the skin that do not contain hair.
b. Merkel Cells are always associated with a nerve ending known as a Merkel
Disc.
B. Layers of the Epidermis (from deep to superficial)
1. Stratum basale-1 cell layer thick. This layer contains stem cells which can divide
to produce the above 4 types of cells as well as the major epidermal derivatives
nails, hair and glands).
2. Stratum spinosum-8-10 cell layers thick. The cells in this layer are tightly packed
together.
3. Stratum granulosum-3-5 cell layers thick. Cells here store keratohyalin which is
used in the production of keratin.
4. Stratum lucidum-very thin layer of cells found only in thick skin. The cells in this
layer are dead-they are too far away from a blood supply to survive. This layer is
commonly found in areas such as the palms of the hands and the soles of the feet.
5. Stratum corneum-25 cell layers thick. Is the most superficial layer of the
epidermis.
a. This layer is composed entirely of dead cells. Is often referred to as the
horny layer.
b. The stratum corneum plays a major role in protecting the body from foreign
invaders.
c. Dead keratinocytes flake off the epidermis as tiny specks known as
dander. Dandruff on the scalp is composed of dead keratinocytes and
sebum (oil).
C. Keratinization-the process in which cells develop in the Stratum Basale and migrate
upwards over time.
1. This process is what allows for the formation of new cells throughout the
epidermis.
2. Typically, it takes 2-4 weeks for new cells to reach the stratum corneum.
3. This process is regulated by the hormone Epidermal Growth Factor (EGF).
V. THE DERMIS-the deeper portion of the skin. Is composed of flexible, strong connective tissue
(including collagen fibers).
A. The dermis contains an extensive nerve and blood supply.
B. Layers of the Dermis:
1. The Papillary Layer-composed of areolar connective tissue with numerous
collagen fibers.
a. Dermal Papillae-projections associated with the papillary region. These
extend upward into the epidermis. Dermal papillae contain nerve endings,
and capillaries.
1) When capillaries in this layer are damaged by friction or burns, fluid
can leak out of the capillaries to form blisters.
2) On the palms of the hands and the soles of the feet, the dermal
papillae form upward projections known as dermal ridges.
Together, the dermal papillae and dermal ridges produce what are
known as friction ridges (fingerprints). The arrangement of
these ridges is genetically determined and it is thought that these
ridges help us grip objects.
3) Meissner’s Corpuscles-located in this region of the dermis. These
are involved in detecting touch stimuli.
2. The Reticular Layer-makes up the bulk of the dermis. This layer provides the skin
with extensibility (the ability to stretch) and elasticity.
a. Striae-small tears in this layer of the skin. These are known as stretch
marks.
b. Pacinian Corpuscles-nerve endings here; these are sensitive to pressure
changes.
C. The Subcutaneous Layer-a layer composed of areolar and adipose tissue that sits
between the dermis and the underlying muscles and tissue. This layer is also referred to
as The Hypodermis.
VI. PIGMENTS THAT PROVIDE US WITH OUR SKIN COLOR PATTERNS:
A. Melanin-brown or black pigment. Is stored in melanocytes.
1. All individuals have about the same number of melanocytes; however, differences
in skin color patterns are caused by differences in the amount of melanin in the
melanocytes. Melanin production is genetically determined.
2. Melanin protects the skin and the body from high levels of ultraviolet sunlight.
3. Freckles-form when melanin accumulates in patches.
4. Albinism-inherited inability of an individual to produce melanin.
5. Vitiligo-partial loss of melanocytes from a small portion of the skin.
B. Carotene-yellow-orange pigment. This can be converted to vitamin A which aids in vision
and proper skin growth and development.
C. Hemoglobin-red pigment in blood.
D. Skin Color Clues:
1. Cyanosis
2. Jaundice
3. Erythema
4. Pallor or blanching
5. Bronzing
6. Bruises
E. Hemangiomas-birth marks. Their color is the result of the accumulation of numerous
blood vessels.
VII. EPIDERMAL DERIVATIVES-all develop from the embryonic epidermis, and they all play a role in
maintaining body homeostasis.
A. Glands-2 Types Associated with the Skin:
1. Sudoriferous (Sweat) Glands-2.5 million of these distributed over the entire
surface of the human body.
a. Two Types of Sudoriferous Glands:
1) Eccrine Sweat Glands-most numerous type of sweat gland. Are
more numerous on the palms of the hands, soles of the feet and
the forehead.
2) Apocrine Sweat Glands-located in the axillary region and they open
directly into hair follicles. These are activated by nerves during pain
and stress. The exact function of these glands is unclear.
b. Perspiration (Sweat)-cools the body and removes nitrogenous wastes from
the body.
1) It is about 99% water but sweat may include salt, urea, uric acid.
2) Sweat production and release is regulated by the hypothalamus.
c. Specialized Sweat Glands:
1) Ceruminous Glands-modified apocrine sweat glands that line the
external ear canal. These produce cerumen (earwax) which serves
as a protective barrier in the ear.
2) Mammary Glands-secrete milk after childbirth.
2. Sebaceous (Oil) Glands-located all over the body except for on the palms of the
hands and the soles of the feet. These glands open into hair follicles.
a. Sebum-oil secreted by these glands. The functions of sebum include:
softening and lubricating the hair and skin, reducing water loss from the
skin and preventing bacterial growth on the surface of the skin.
b. The secretion of sebum is stimulated by hormones (especially the sex
hormones).
c. Acne-inflammation of sebaceous glands that leads to the formation of
pimples.
d. Blackheads-occur when some bacteria begin feeding on sebum.
e. Seborrhea-overactive sebaceous glands on the skull of an infant. This is
known as “cradle cap.”
B. Nails-located at the ends of the fingers and toes.
1. The major parts of nails include: the body, the root, the lunula, the cuticle, the free
edge.
C. Hair (Pili)-mostly composed of dead, keratinized cells.
1. Hair Anatomy:
a. Shaft
b. Hair Root
c. Hair follicle
d. Bulb-enlarged region at the base of the hair follicle. This contains the
Papilla of the Hair which houses blood vessels and oil glands.
2. Arrector pili muscle-smooth muscle fibers that connects the follicle to the
underside of the epidermis. This muscle pulls the hair upright to form dimples on
the skin.
3. Hair growth is most influenced by nutrition and hormones (especially
testosterone).
4. Alopecia-hair thinning or balding.
5. Male Pattern Baldness
VIII. SKIN CANCER
A. Basal cell carcinoma-least malignant and most common type of skin cancer. Is most
common in areas exposed to direct sunlight. This is easily treated.
B. Squamous cell carcinoma-arises from keratinocytes in the stratum spinosum. Can grown
and spread quickly. Early detection, surgical removal and radiation all are effective ways to
cure this cancer.
C. Melanoma-cancer of melanocytes. Is rare but its incidence is increasing. Early detection
is a key here.
D. ABCD Rule-Asymmetrical, Border, Color, Diameter.
IX. BURNS
A. First degree burns
B. Second degree burns
C. Third degree burns
XI. SKIN DISORDERS
A. Albinism-genetic inability to produce melanin.
B. Boils and Carbuncles-bacterial infection of the skin that extends into the subcutaneous
layer.
C. Cold sores-herpes infection that accumulates around moist or mucus regions of the body.
D. Contact dermatitis-redness and itching of the skin due to chemicals that come in contact
with the skin.
E. Decubitis (Bed Sores)-reduced blood flow to regions over a bony prominence. This often
leads to tissue death.
F. Impetigo-light red rash that is bacterial in nature.
THE SKELETAL SYSTEM
I. Bone tissue is an ever-changing, growing, developing tissue in the human body. It serves as the
major support tissue for the human body.
A. Osteology
II. FUNCTIONS OF BONE TISSUE
A. Support-bone provides a framework for the human body. It supports soft tissues and
serves as a region for muscle attachment.
B. Protection
C. Movement-skeletal muscle attaches to and moves bones.
D. Mineral Storage-bone is a reservoir for calcium and phosphate. On demand, bone tissue
can release both of these minerals into the bloodstream for use in the human body.
1. Due to this, bone plays a key role in electrolyte balance in the body.
2. Bone tissue also helps maintain acid-base balance in the body by absorbing or
releasing alkaline salts like calcium phosphate.
E. Blood Cell Production
1. Hemopoiesis (hematopoiesis)-the formation/production of blood cells. This
process takes place in red bone marrow.
F. Energy Storage
1. Yellow Bone Marrow-associated with bone. This material is composed of adipose
tissue and scattered leukocytes. The adipose tissue serves as a source of energy
for the human body.
G. Production of Osteocalcin-a hormone that helps regulate insulin secretion and sugar
homeostasis in the body.
H. Detoxification-bone absorbs heavy metals from the blood; thus, reducing their effects on
body. Bone can slowly release these compounds via secretion.
III. ORGANIZATION OF THE SKELETAL SYSTEM
A. The human skeleton is composed of 206 bones dispersed throughout the body. These bones
are classified into two major skeletal divisions:
1. The Axial Skeleton-bones located along the central axis of the body. These bones
typically protect and support body structures.
2. The Appendicular Skeleton-bones of the extremities. These bones are involved in
movement.
B. Types of Bones in the Human Skeleton-based on shape.
1. Long Bones-are longer than they are wide. They are named for their elongated shape,
not their length.
a. Are typically curved. The curvature acts to increase their strength which allows
them to withstand great stress; thus reducing the chance of fracture.
b. The Major Parts of a Long Bone:
1) Diaphysis-the shaft of the bone.
2) Epiphyses-the ends of the bone. These are covered and protected by
hyaline cartilage.
3) Metaphysis-the region in a mature bone where the diaphysis meets the
epiphysis. This region of the bone contains the epiphyseal plate-region
where cartilage is replaced by bone. The epiphyseal plate is involved in
bone growth.
4) Hyaline (Articular) Cartilage-a layer of cartilage that covers the ends of
a long bone. The cartilage serves as a shock absorber between bones.
5) Periosteum-a membrane that surrounds the surface of a bone. It is
composed of 2 Layers:
a) An outer fibrous layer that is composed of dense irregular
connective tissue. This layer contains blood vessels, nerves and
lymphatic vessels that pass into the bone.
b) An inner osteogenic layer that contains elastic fibers, blood
vessels and bone cells.
c) Overall, the periosteum is involved in bone growth, repair and
development. It also serves as a site of attachment for
ligaments and tendons.
d) Sharpey’s Fibers-collagen fibers that anchor the periosteum to
the bone. Some of these penetrate into the bone where they are
known as Perforating Fibers.
6) Medullary (Marrow) Cavity-an open space within the diaphysis of a
bone. It contains yellow bone marrow which serves as an energy source
in bone. If a person becomes anemic, yellow marrow can revert to red
bone marrow to aid in the production of additional red blood cells.
7) Endosteum-a membrane that covers and lines the medullary cavity of a
bone. It contains 2 specialized types of bone cells: osteoprogenitor
cells and osteoclasts.
2. Short Bones-are cube-shaped. Internally, these are composed of thin plates of spongy
bone known as diploe. The diploe are covered by a layer of compact bone tissue.
a. The carpals and tarsals are examples of short bones.
3. Flat Bones-are very thin bones. The cranial bones, sternum and ribs are flat bones.
a. These are composed of 2 plates of compact bone tissue that encloses a layer
of spongy bone (diploe).
b. These bones provide considerable protection, and they offer a great surface
area for tendon and ligament attachment.
4. Irregular Bones-have complex shapes. The vertebrae of the spinal column and some facial bones are classified as irregular bones. These are also composed of diploe.
5. Sesamoid Bones-small bones embedded in tendons in the body. The patella is an
example.
IV. HISTOLOGY OF BONE TISSUE
A. Overall, bone tissue is composed of 5 types of cells that are embedded in a thick, hardened
matrix.
B. Bone Matrix-is composed of about 25% water, 25% protein (collagen), and 50% mineral salts
(calcium carbonate and calcium phosphate).
1. Calcification (Mineralization)-the formation of new matrix. This occurs as the above
mineral salts accumulate over collagen fibers. The collagen fibers act to provide
strength to the matrix.
2. In bone, collagen fibers are held together by sacrificial bonds that easily break and
reform to dissipate energy from force on bones.
C. 5 Types of Cells in Bone Tissue:
1. Osteoprogenitor (Osteogenic) cells-unspecialized cells derived from mesenchyme.
These cells are capable of undergoing rapid cell division. These can develop into
osteoblasts.
a. Osteoprogenitor cells are located near blood vessels in the periosteum and
endosteum of bone.
2. Osteoblasts-secrete collagen and other materials needed to build bone tissue. These
have lost the ability to undergo cell division. These cells function by secreting new
bone matrix.
a. These are located on the surface of bone tissue.
b. When osteoblasts are completely surrounded by matrix, they are referred to as
Osteocytes.
3. Osteocytes-mature bone cells. These cells have lost the ability to divide. Osteocytes
do not secrete bone matrix. They are involved in nutrient/waste exchange between
bone and blood.
a. These cells regulate the daily activities of bone tissue.
b. These also serve as stress sensors in bone to monitor bone overload.
4. Bone Lining Cells-these are thought to help maintain the health of bone matrix.
5. Osteoclasts-are involved in bone resorption (the destruction of bone matrix). These
play a key role in bone growth and repair.
a. These cells release acids and enzymes that degrade bone tissue.
b. Structurally they contain a ruffled border that increases surface area of the cell
which increases enzyme release and bone degradation.
D. 2 Types of Bone Tissue: Compact Bone and Spongy Bone.
E. Compact Bone Tissue
1. Compact bone forms the external layer over all bones in the body. It also makes up the
diaphysis of long bones.
2. Compact bone is composed of repeating units known as Haversian Systems
(Osteons).
3. Structure of a Haversian System:
a. Haversian (Central) Canals-run longitudinally in bone tissue. These contain
blood vessels and nerves.
b. Lamellae-rings of matrix in bone. This is composed of the mineral salts calcium
carbonate and calcium phosphate.
c. Volkmann’s Canals-run horizontally in bone tissue. These also contain blood
vessels and nerves.
d. Lacunae-small spaces in the lamellae of compact bone. Osteocytes are in
these spaces.
e. Canaliculi-small channels extending from lacunae. These serve as
passageways through which nutrients and wastes can pass.
F. Spongy Bone Tissue-contains many open spaces.
1. Spongy bone tissue is composed of thin plates of bone known as trabeculae. It does
not contain Haversian Systems.
2. The spaces between trabeculae are filled with red bone marrow which is involved in
blood cell production.
3. Osteocytes are located in the trabeculae.
4. Spongy bone tissue is found in: short bones, flat and irregular bones and in the
epiphyses of long bones. Specifically, spongy bone is found in the sternum, ribs, skulls,
and vertebrae.
G. Bone contains a large supply of blood. Nutrient arteries carry blood into the diaphysis of long
bones. These enter the bone through nutrient foramina.
1. Epiphyseal arteries carry blood into the epiphyses of a bone.
V. BONE FORMATION (OSSIFICATION)
A. Bone is a dynamic, ever-changing type of tissue. Ossification is the process by which bone
forms.
B. 2 Patterns of Ossification in the Human Body:
1. Intramembranous Ossification-bone formation directly on or over loose fibrous
connective tissue.
a. No cartilage stage is present in bones that form in this fashion.
b. This process occurs in only a few developing bones. Often times, the bones
formed during intramembranous ossification are soft at birth. The skull bones,
the clavicle and the mandible form in this fashion,
. 2. Endochondral Ossification-bone formation over hyaline cartilage.
a. Most human bones form in this manner.
VI. BONE GROWTH-IN LENGTH
A. Bone growth in length generally ends before the age of 25; however, bones may continue to
thicken throughout a person’s life. Length growth may stop earlier in females than in males.
B. Events in Length Growth of Bone:
1. Epiphyseal Plate-a layer of hyaline cartilage in the metaphysis of a growing bone.
C. Final Points on Length Growth in Bones:
1. The epiphyseal plate is the only area in a bone where length growth can occur.
Eventually, cells in the epiphyseal plate stop dividing. At this point, bone tissue
replaces the cartilage. This produces a remnant known as the epiphyseal line.
2. Fractures of the epiphyseal plate can result in a cessation of bone growth. Due to this,
a fractured bone may be shorter than its counterpart.
3. Bone growth usually stops before the age of 25. In general, length growth ends earlier
in females than in males.
VII. BONE GROWTH-IN THICKNESS-this occurs as osteoblasts secrete new matrix to the periosteum of
a bone.
VIII. HORMONAL REGULATION OF BONE GROWTH
A. Human Growth Hormone (HGH)-secreted by the pituitary gland. This hormone regulates bone
growth prior to puberty. Oversecretion of this hormone may lead to gigantism; whereas
undersecretion may lead to dwarfism.
B. At puberty, the sex hormones estrogen and testosterone stimulate changes in the human
skeleton. These hormones are responsible for the growth spurt that occurs at puberty. They
also stimulate the skeleton to develop into the typical male and female shape.
C. Thyroid Hormones-also play a role in bone growth and development.
IX. BONE REMODELING-the ongoing replacement of old bone tissue by new bone tissue.
A. Bone is an ever-changing type of tissue. Remodeling removes worn and injured bone tissue
and replaces it with new, healthy bone tissue. This ensures that bone remain healthy.
B. Osteoclasts-bone cells that are responsible for removing old bone matrix (bone resorption).
1. These cells breakdown matrix by secreting protein-digesting enzymes and various
acids.
2. Once old bone matrix has been removed, osteoblasts secrete new matrix.
C. Alkaline phosphatase-an enzyme that regulates the formation of calcium carbonate and
calcium phosphate This enzyme is needed in large supplies for bone remodeling to occur.
D. Vitamins and Minerals that are needed for Bone Remodeling to occur:
1. Calcium
2. Vitamin C-needed for the formation of collagen fibers.
3. Vitamin D-needed for the absorption of calcium.
4. Vitamin A-maintains a balance between bone deposit and bone resorption.
X. FRACTURE-refers to any break in a bone.
A. The repair of a fracture is a slow and painful process.
B. Types of Fractures
C. The Clavicle is the most commonly broken bone in the human body.
XI. BONE AND CALCIUM HOMEOSTASIS
A. Bone is the major calcium reservoir in the human body. Bones store 99% of the body’s
calcium.
B. Uses of Calcium in the Human Body:
1. Regulation of muscle contraction
2. Impulse formation and conduction in the nerve tissue
3. Blood clotting
C. Parathyroid Hormone (PTH)-hormone that stimulates osteoclasts to release calcium into the
blood under times of need.
D. Calcitonin-secreted by cells in the thyroid gland.
1. When calcium levels rise above normal in the bloodstream, calcitonin responds by decreasing the activity of osteoclasts. It also increases the activity of osteoblasts.
Overall, this reduces calcium levels in the bloodstream.
XII. SURFACE MARKINGS-bones contain a number of surface features that serve as points of
attachment, openings and depressions etc..
A. Recall that the skeleton is composed of 206 bones and it is divided into an Axial and
an Appendicular Portion.
XIII. THE SKULL
A. Is comprised of 2 major regions: the cranium and the facial region.
B. Bones of the Cranium:
1. Frontal Bone
2. Parietal Bones-form the majority of the sides of the skull.
3. Temporal Bones-
a. Temporal Squama-forms the temple.
b. Zygomatic Arch-connects to the zygomatic arch to form part of jaw.
c. Carotid Canal-carotid artery passes through here. Since this artery is
close to the ear, you can often hear your heartrate, and you may feel a pounding sensation in this area during heavy activity.
d. Jugular Foramen-jugular vein and 3 cranial nerves pass through here.
e. Mandibular Fossa-forms part of the temporomandibular joint (TMJ).
f. Temporomandibular joint-between temporal bone, mandible.
g. Mastoid Process-bump behind the ear. Neck muscles attach here.
h. Styloid Process-site for neck, tongue muscles and ligaments that hold
the hyoid bone in place.
4. Occipital Bone-back of skull.
a. Foramen Magnum-site where the spinal cord passes through to attach
to the brain.
5. Sphenoid-forms the bat in the middle of the skull. It articulates will all cranial
bones; therefore, it is often called the keystone bone of the cranium.
a. Sella Turcica-surrounds and holds the pituitary gland in place.
6. Ethmoid-at front of skull, upper portion of nasal cavity, forms part of the orbits.
The ethmoid connects to all of the bones of the skull and face-it essentially
holds all of the bones in place. It is the most deeply situated bone of the skull.
a. Cribriform Plate-forms the roof of the nasal cavity. Contains numerous
holes known as the olfactory foramina through which olfactory nerves
pass.
b. Perpendicular plate-forms part of the nasal septum.
7. Major Sutures of the Skull:
a. Coronal suture-separates the frontal bone and the parietal bones.
b. Lambdoid suture-separates the parietal bones from the occipital bone.
c. Squamous suture-separates the temporal bones from the parietal bones.
d. Sagittal suture-separates the parietal bones from each other
8. Developmental Aspects of the Skull
a. The bones of the skull develop via intramembranous ossification.
b. Due to this, the skull bones are not fully ossified at birth. Instead, the
bones are composed of fontanelles (soft spots) which allow the infant’s
head to be compressed during birth and they accommodate brain growth.
C. Facial Bones of the Skull
1. Nasal Bones-form the bridge of the nose, are primarily cartilage in composition.
2. The Vomer-unpaired facial bone that forms part of the nasal septum.
a. Nasal Septum-separates the right and left airways in the nose. b. Deviated nasal septum-physical disorder in which the vomer is pushed to
one side or another. Is often caused by trauma to the face.
3. Maxillae-form the upper jaw. These paired bones hold the upper teeth in place
and they form the boundaries of three cavities: the roof of the mouth, the floor
of the nose and the floor of the orbits.
a. Cleft palate-condition in which the maxillary bones are not completely
joined. This often leads to a cleft lip. This condition is often repaired via
surgery.
4. Zygomatic Bones-cheek bones.
5. The Mandible-largest and strongest bone of the face. It forms the lower jaw
bone. It holds the lower teeth in place. This is the only movable skull bone.
a. Mental foramen-passageway for nerves to the chin.
6. The Lacrimal Bones-smallest and most fragile bones of the face.
a. Lacrimal fossa-allows tears to drain off of the eye to the nasal cavity.
7. The Palatine Bones-form the underside of the nasal cavity and part of the orbits.
8. The Paranasal Sinuses-open spaces in some skull bones. These help filter incoming
air and they provide tone to our voice.
9. The Hyoid Bone-where is this bone located?
a. It serves as a movable base for the tongue.
b. It is the only bone of the body that does not articulate with another bone.
XIV. THE VERTEBRAL COLUMN
A. Region of the Vertebral Column-How many vertebrae are in each region?
1. Cervical Region-
2. Thoracic Region-
3. Lumbar Region-
4. Sacral Region-
5. Coccygeal Region-
B. Normal Curves of the Vertebral Column
1. Cervical Curve and Lumbar Curve-posteriorly concave.
2. Thoracic Curve and Sacral Curve-posteriorly convex.
3. What is the significance of these curves?
C. Verebrae-bones that make up the spinal column. The major parts of a vertebra include:
1. Intervertebral Discs-cartilage pad between the vertebrae.
a. Composed of an inner gelatin layer known as the nucleus pulposus
which is surrounded by a strong annulus fibrosis.
b. The discs serve as shock absorbers between the vertebrae.
2. Body(Centrum)-major weight-bearing structure.
3. Vertebral Arch-also bears weight.
4. Vertebral Foramen-what passes through here?
5. Intervertebral Foramina-nerves pass through these.
6. Processes on Vertebrae: Where are each of these located?
a. Spinous Process
b. 2 Transverse Processes
c. Articular Processes
E. Cervical Vertebrae-where are these located?
1. These are the smallest of the vertebrae and their spinous processes are bifid.
2. The Atlas-where is this located? It does not have a spinous process.
3. The Axis-where is this located?
a. The Dens (Odontoid Process)-pivot point on the axis for skull rotation.
F. Thoracic Vertebrae-where are these located?
1. These attach to the ribs. Their vertebral foramen is circular.
G. Lumbar Vertebrae-largest of the vertebrae. There are modified for support.
1. Their vertebral foramen is triangular.
H. The Sacrum-triangular bone, composed of 5 fused vertebrae.
1. Sacral Foramina-holes through which nerves and blood vessels pass through.
I. The Coccyx-what is this structure?
1. For the most part, it is considered to be a useless bone.
XV. THE STERNUM
A. Major Regions of the Sternum:
1. The Manubrium-superior portion, clavicle attaches here at the clavicular notch.
a. Jugular notch-superior portion of the manubrium.
2. The Body-attaches to cartilages from ribs 2-7
3. Xiphoid Process-primarily cartilage, becomes hardened (ossified) as we age.
a. Abdominal muscles attach here.
b. Landmark for CPR.
XVI. RIBS-everyone has 12 pairs of ribs.
A. True Ribs-their cartilage attaches directly to the sternum. False Ribs-their cartilage
does not attach directly to the sternum. Floating Ribs-do not attach to the sternum at all.
B. Parts of a Rib
1. The Head-attaches to the vertebrae, the neck is near the head of a rib.
2. The Shaft-forms the length of a rib. Has a costal groove where nerves and
blood vessels are located.
XVII. THE CLAVICLE
A. Acromial Extremity-site where the clavicle articulates with the acromion.
XVIII. THE SCAPULA
A. Acromion-upper portion of scapula, forms the Acromioclavicular joint with the
clavicle.
B. Glenoid Cavity-fossa where the humerus attaches to form the shoulder joint.
XIX. THE HUMERUS
A. The Head-articulates with the glenoid cavity to form the shoulder joint.
B. The Greater Tubercle-knob, where major muscles attach.
C. The Lesser Tubercle-smaller knob, major muscle also attach here.
D. The Deltoid Tuberosity-site where the deltoid muscle attaches.
E. The Olecranon Fossa-forms part of the elbow joint.
F. The Medial and Lateral Epidcondyles-bumps, sites of muscle attachment.
XX. THE ULNA
A. The Olecranon Process-prominence of the elbow.
XXI. THE RADIUS
A. The Head-nail-shaped structure that articulates with the ulna.
B. The Radial Tuberosity-site for muscle attachment.
XXII. THE HAND
A. Carpals-8 bones that form the wrist.
B. Metacarpals-5 bones that from the palm of the hand.
C. Phalanges-14 of these in each hand, these form the fingers.
XXIII. BONES OF THE PELVIC GIRDLE
A. THE ILLIUM
1. Sacroiliac Joint-site where the sacrum and ilium attach.
B. THE ISCHIUM
1. The Obturator Foramen-large hole, blood vessels and nerves pass through here.
It is nearly closed by a fibrous membrane.
2. The Acetabulum-deep socket that receives the head of the femur or thigh bone.
C. THE PUBIS BONE
1. The Pubic Symphysis-formed by the rami of the pubic bones. This symphysis
is held together by fibrocartilage. The pubic symphysis forms the pubic arch.
2. The female pubis is wider in females to allow for childbirth.
XXIV. THE FEMUR
A. Head of the Femur-forms the pelvic girdle
B. Greater and Lesser Trochanters-knobs, for major muscle attachment, including the
gluteal muscles.
C. The Medial and Lateral Condyles-articulate with the same structures of the tibia to
form the knee joint.
D. The length of the femur is approximately one-fourth of a person’s height.
E. The medial portion of the femur is more pronounced in women due to their wider
pelvis. This contributes to a greater incidence of knee injuries in women athletes.
XXV. THE PATELLA-what is this?
A. Increases leverage of the leg. Is held in place by the patellar ligament.
XXVI. THE TIBIA-second largest bone of the body.
A. The Medial and Lateral Condyles-articulate with femur to form knee joint.
B. The Medial Malleolus-forms the medial knob of the ankle.
C. The Tibial Tuberosity-site for patellar ligament attachment.
XXVII. THE FIBULA
A. The Lateral Malleolus-forms the lateral side of the ankle.
XXVIII. THE FOOT
A. Tarsus-contains the tarsal bones which includes the calcaneus and talus.
B. Metatarsus-composed of metatarsal bones.
C. Phalanges-toes
D. Arches of the foot-for support.
XXIX. JOINTS-are defined as points of contact between bones, cartilage and bones, and teeth and
bone.
A. Joints serve two major functions: they provide mobility, and they hold the skeleton
together.
XXX. TYPES OF JOINTS
A. Fibrous Joints-no synovial cavity present. The bones are held together by fibrous
connective tissue.
B. Cartilaginous Joints-no synovial cavity present, cartilage holds the joint together.
C. Synovial Joints-have a synovial cavity. The bones are held together by ligaments.
1. Types of Synovial Joints
a. Gliding joints-bones can only move side-to-side in these.
b. Hinge joints-convex surface of one bone fits into the concave surface of
another bone.
c. Pivot joints-the rounded portion of one bone articulates with a
bone/ligament ring of another bone.
d. Condyloid joints-condyle of 1 bone fits into an elliptical cavity of another
bone.
e. Saddle joints-the articular surface of one bone is saddle-shaped and the
second bone appears as a rider on the saddle.
f. Ball and Socket Joints-the ball (head) of one bone fits into a depression on
the second bone.
XXXI. DISORDERS ASSOCIATED WITH THE SKELETAL SYSTEM
A. Osteoporosis-a condition of porous bone. It is characterized by decreased bone mass and
increased susceptibility to fracture. Has been treated with calcium and vitamin D
supplements. Exercise appears to reduce (an in some cases prevent) the onset of
osteoporosis. Hormone replacement therapy has also been used as a means for treating
osteoporosis. Osteoporosis is a form Osteomalacia-bone softening due to inadequate
supplies of Vitamin D.
B. Paget’s disease-accelerated remodeling. Causes weak areas in bone tissue.
C. Osteoarthritis-the degeneration of hyaline cartilage.
D. Rickets-a form of osteomalacia that occurs in children. Is usually associated with vitamin D
deficiency. Drinking vitamin D fortified milk usually alleviates this illness.
E. Herniated disc-characterized by the protrusion of the inner layer of an intervertebral disc. Can
be repaired via surgery.
F. Abnormal curves of the Vertebral Column:
1. Scoliosis-a lateral bending of the vertebral column, usually in the thoracic region.
2. Kyphosis-an exaggeration of the throacic curve of the vertebral column.
3. Lordosis-an exaggeration of the lumbar curve of the vertebral column.
CHAPTER 7-THE MUSCULAR SYSTEM
I. MYOLOGY-the study of muscle tissue. Muscles account for 40-50% of total body weight.
A. Muscles are capable of converting chemical energy (ATP) into mechanical energy. This
mechanical energy is used to generate force and to produce muscle movements.
II. TYPES OF MUSCLE TISSUE
A. Skeletal muscle-attaches to and move bone.
1. Striated and Voluntary.
2. Skeletal muscle fibers are multinucleate.
B. Cardiac muscle-located in the wall of the heart.
1. Striated and Involuntary.
2. Cardiac fibers are uninucleate.
C. Smooth muscle-located in the internal organs and most blood vessels.
1. Nonstriated and Involuntary.
2. Smooth muscle fibers are uninucleate.
III. FUNCTIONS OF MUSCLE TISSUE
A. Movement-skeletal muscles contract (shorten) to pull on bones.
B. Moving Compounds within the Human Body-smooth muscle in blood vessels and the
internal organs regulate movements of materials within these structures.
C. Maintaining Posture-skeletal muscles provide us with our posture.
D. Regulating organ volume-sphincter muscles play a role in this function.
E. Thermogenesis-heat production. As muscles work and contract, they generate a great
deal of heat. Muscles can generate as much as 85% of our body heat.
1. Shivering-involuntary contractions of skeletal muscles. This greatly increases body
temperature when one is cold.
IV. CHARACTERISTICS OF MUSCLE TISSUE
A. Excitability-the ability to respond to a stimulus by producing electrical signals(impulses)
within the body. This is also a major property of nerve tissue. This property of muscles is
triggered by and regulated by neurotransmitters and hormones.
B. Contractility-the ability of a muscle to shorten and thicken (contract), thus, generating
force to do work. This characteristic is unique to muscle tissue.
C. Extensibility-the ability of a muscle to stretch without damage to the tissue.
D. Elasticity-the ability of a muscle to return to its original shape after stretching or
contracting.
V. ANATOMY AND GENERAL FEATURES OF SKELETAL MUSCLE TISSUE
A. Each skeletal muscle is composed of numerous muscle fibers. These fibers are
essentially muscle cells.
B. Tendons-connective tissue cords that attach muscle to bone (specifically to the
periosteum of bone).
C. Nerve Supply in Skeletal Muscle
1. Muscles have an extensive supply of nerves.
2. Motor Neurons-nerve cells that stimulate muscles to contract. These deliver the
impulse that causes a muscle to contract.
a. Motor unit-a motor neuron and all of the skeletal muscle fibers it
stimulates.
3. The Neuromuscular Junction-the site where nerve cells and muscle fibers meet.
a. Synapses-the actual site where a neuron meets a muscle fiber.
1) Impulses are carried from the motor unit to the muscle fiber by the
neurotransmitter Acetylcholine.
VI. MICRSOCOPIC ANATOMY OF MUSCLE FIBERS
A. Muscle tissue is composed of thousands of long, thin cells known as myofibers.
1. Muscle fibers run parallel to each other.
2. Parts of a Skeletal Muscle Fiber:
a. Sarcolemma-plasma membrane around a muscle fiber.
b. Sarcoplasm-cytoplasm of the muscle fiber.
c. Myofibrils-small thread-like structures in the sarcoplasm of muscle fibers.
These are the contractile elements of the muscle fiber.
d. Numerous mitochondria that are involved in aerobic cellular respiration.
B. More on Myofibirils
1. These have a role in muscle contraction.
2. 2 Types of Filaments in Myofibrils
a. Thick filaments
b. Thin filaments
3. Overall, the thick and thin filaments overlap each other.
4. The filaments that make up the myofibrils are found in compartments known as
sarcomeres. Sarcomeres are the basic functional units of striated muscle fibers.
5. Organization and Structure of a Sarcomere
a. Z Discs (Lines)-plates that separate one sarcomere from another.
b. The A Band-within each sarcomere. This is a dark area that contains thick
filaments and the portion of the thin filaments that overlap the thick filaments.
c. The I Band-a light region that contains only thin filaments.
1) This band does not contain thick filaments.
2) The Z Disc passes through the center of the I Band.
3) The alternating striations of muscle tissue is produced by the
alternating dark A band and the light I bands.
d. The H Zone-located in the center of each A Band. it contains thick filaments
but not thin filaments.
6. 2 Contractile Proteins in Myofibrils: Myosin and Actin
7. Myosin-forms the thick filaments.
a. Myosin tails-These point towards the M line in the center of the sarcomere.
b. Myosin cross bridges (Myosin heads)-extend towards the thin filaments.
8. Actin-forms the bulk of the thin filaments.
a. Myosin binding sites-on each actin molecule. Myosin cross bridges can
attach to these myosin binding sites.
b. 2 Regulatory Proteins in the Thin Filaments
1) Tropomyosin-covers the myosin binding sites on actin molecules
when muscles are relaxed. This protein blocks the attachment of
myosin heads to actin.
2) Troponin-holds the tropomyosin in place in relaxed muscle tissue.
9. The Sarcoplasmic Reticulum (S.R.)-fluid filled bags that encircle each myofibril.
a. Calcium is stored in special terminal cisterns within the SR. Impulses can force
calcium release from the terminal cisternae into the muscle fiber.
b. The impulses reach the terminal cisternae by traveling down T-Tubules.
VII. MUSCLE PHYSIOLOGY THE EVENTS THAT OCCUR IN MUSCLE CONTRACTION
A. The Sliding Filament Mechanism of Muscle Contraction-states that skeletal muscle shortens
as the thick and thin filaments slide past one another. During a muscle contraction, myosin
heads pull on the thin filaments, causing them to slide inwards towards the H zone.
B. Adenosine Triphosphate (ATP)-an energy source for living cells. This is produced by
aerobic cellular respiration.
C. Steps in a Muscle Contraction
1. Impulse travels from an axon to a muscle fiber (as discussed earlier).
2. The impulse initiates the release of calcium from the S.R.
a. Calcium levels rise in the sarcoplasm of the muscle fiber.
b. Due to the increased levels of calcium, troponin and tropomyosin move away
from the myosin binding sites on actin molecules (in the thin filaments).
3. At this point, the ATP associated with the myosin cross bridges donates energy to the
cross bridges. The myosin cross bridges then attach to the free myosin binding sites
on the actin molecules.
4. Following this attachment, the myosin heads turn towards the center of the
sarcomere. This pulls the thin filaments past the thick filaments towards the H zone.
This is the actual contraction.
5. Once the power stroke is complete, ATP attaches to the myosin cross bridges. The
energy associated with the ATP forces the myosin heads to detach from the actin
molecules.
6. The myosin cross bridges and actin molecules return to their original position.
7. Tropomyosin and troponin cover the myosin binding sites on the actin molecules.
8. Calcium is pumped into the S.R. by special calcium pumps on the membrane of the
S.R. Calcium levels decrease in the sarcoplasm.
D. The All or None Principle of Muscle Contraction-muscles contract to their fullest extent or
they do not contract at all. In contractions, the thick filaments slide past the thin filaments.
VIII. MYOGRAM-the record of a muscle contraction.
A. Phases in a Typical Myogram
1. The Latent Period-brief period of time between the application of an impulse and the
beginning of a muscle contraction.
2. The Contraction Period-
3. The Relaxation Period-
4. The Refractory Period-the period during which a second contraction cannot occur.
IX. VARIOUS TYPES OF MUSCLE CONTRACTIONS
A. Twitch Contractions-a brief contraction of all the muscle fibers in a motor unit of a muscle in
response to a single impulse.
B. Wave Summation-occurs when 2 stimuli are applied, and the second one is delayed until
the refractory period is over.
C. Tetanus-a sustained contraction in which a muscle can only partly relax between impulse
stimulation. Complete vs. Incomplete Tetanus
D. Staircase Effect (Treppe)-occurs when a muscle has been relaxed for some period of time
and then is stimulated to contract. In this case, the first few contractions is stronger than
the previous contractions.
X. CRITERIA USED TO NAME SKELETAL MUSCLES
A. Function of the muscle
B. Shape of the muscle
C. Location of the muscle
D. Site of Muscle Attachment
E. Size of the muscle
F. Orientation of the muscle fibers
XI. TERMS RELATED TO MUSCLE ACTIVITY
A. Origin-less movable attachment of a muscle to a bone. Is usually closer to the axial
skeleton.
B. Insertion-more movable attachment of a muscle to a bone, usually near the
appendicular skeleton.
C. Action-the desired movement produced by a muscle.
D. Prime mover-muscle that that contracts to produce an action.
E. Antagonist-muscle that relaxes when another muscle contracts.
F. Synergists-muscles that steady the movements of a prime mover.
XII. TERMS RELATED TO MUSCULAR MOVEMENTS
A. Flexion
B. Extension
C. Abduction
D. Adduction