Cheryl's A&P Blog

The Upper Limb

2006-04-09T21:33:00.000-07:00

The Upper Limb Broken Down

Bones

Bones of the Upper Limb

The single bone of the upper arm is called the humerus, located between the elbow and the shoulder. The humerus articulates (moves) with the scapula (the bone that contains the shoulder blade) to form the shoulder joint, a shallow ball and socket joint that is inherently unstable but allows tremendous freedom of motion. Shoulder surgeons affectionately and accurately call the shoulder joint a "ball in a wall." The joint is supported by a ring of muscles called the rotator cuff that provides stability to the shoulder joint and helps it move. These muscles are prone to injury in the middle years of life and to atrophy (muscle wasting) in later years.
At the distal end of the arm, the humerus ends at the elbow joint. This joint is a hinge-like joint that is quite constrained, but allows over 100 degrees of motion in a single plane and rotation of the forearm.
The forearm has two long bones, the radius and ulna, that form joints with each other and the humerus at the elbow and with each other and the bones of the wrist at the wrist. Flexion of the elbow allows the hand to reach the face and mouth so that we can eat. Rotation of the forearm is accomplished by the radius rotating along its long axis at the elbow and around the ulna at the wrist.

The hand and wrist:

are made up of 27 bones,
the highest number of integrated, coordinated bones per tissue area in the human body.

The Wrist is:

comprised of 8 bones, the carpal bones, aligned in 2 rows.
Motion of the wrist is accomplished by a complicated symphony of interdependent motions between the carpal bones and the radius and ulna.

The hand has:

5 tubular bones called metacarpals that bridge the distance between the wrist and the digits.
Each of the digits, the four fingers and the thumb, has a corresponding metacarpal bone in the hand.
There is very little motion between the metacarpals and the wrist for the index finger and the long finger.
The metacarpal for the thumb is very mobile at its base as are the joints between the wrist and the metacarpals for the ring and small fingers.

Tissue

All bones are composed of bony tissue

The 4 functions of bony tissue:

support & movement
protection
mineral storage (calcium)
blood cell development in long bone marrow

Bony tissue consists of:
- 35% collagen, ground substance, and cells
- 65% inorganic calcium

The 3 types of bone cells:

1. Osteoblasts which make & deposit the components of bone's extracellular matrix

2. Osteoclasts which break down and resorb bone for remodeling (become phagocytes and degrade calcium)

3. Osteocytes which are mature, spider shaped bone cells that monitor the environment

There are 2 main textures of bony tissue:

1. Compact tissue which is dense tissue containing the Haversian canals (canals through which blood vessels and nerves pass, and surrounded by layer of bone), which is found at the surface of bones. Compact tissue is highly vascularized. In the image of compact bone at right, you can see the Haversian canals and the layers of bone. The image is from McGraw Hill Higher Education website.

2. Spongy tissue, found in the interior of long and skull bones and at the ends of long bones, which provides spaces for bone marrow formation in the trabeculae.
The picture below gives a clear view of where both spongy and compact bones can be found in a typical long bone. Note the spongy tissue is at the end and the inteior of the bone, while the compact bone is at the surface of the bone. The image is from medco.com

Four classes of bones:

1. Long bones are longer than they are wide, and consist of a shaft plus two ends.
2. Short bones are cube-shaped bones.
3. Flat bones are thin, flat, and somewhat curved, such as the skull, ribs, and sternum.
4. Irregular bones have complicates shapes, like the vertebrae and the hip bones.

Muscles

Muscles of the Upper Limb

The major changes in the musculature of the upper limb involve the secondary effects that result from freeing the forelimb from a major supportive or propulsive role.

The biceps, a muscle well known to us, is assisted by other muscles in its action of flexing the elbow joint.
On the back (posterior) surface of the arm, the triceps extends (straightens) the elbow.
On the forearm, the muscles on the flexor surface (where your skin is lighter in color)
flex the wrist and digits; the muscles on the extensor surface (where the skin is usually hairy) extend the wrist and digits.
The small muscles within the hand are called the intrinsic muscles. These small muscles act to coordinate the fine movements of the fingers and thumb.

Nerves

The nerves to the arm exit the spinal cord in the neck and have a complicated intermingling as they pass across the side of the neck and under the collarbone. This area is called the brachial plexus. In the mid-arm the nerves have sorted themselves out to three large nerves of the forearm and hand: the median, ulnar, and radial nerves.

The median nerve:

travels to the hand between the muscles of the forearm. At the wrist, it passes through a tunnel, the carpal tunnel, a common site of compression of the nerve.
The median nerve provides the motor nerves for the muscles that flex the wrist and fingers. The median nerve also serves the small muscles in the ball of the thumb, particularly the muscle that lifts the thumb away from the plane of the hand. The sensation from the thumb, index, and long fingers and half of the ring finger is carried by the median nerve.

The ulnar nerve:

carries the sensation from the small finger and half of the ring finger, as well as the back of the hand on the ulnar side (by the small finger).
The ulnar nerve lies on the ulnar side of the forearm. It passes behind the elbow joint and is susceptible to injuries and compression at this spot. When this nerve receives minor bumps, an electrical shock shoots down the hand, the so-called crazy bone or funny bone.
The muscles supplied by the ulnar nerve aid in flexion of the fingers and power most of the small muscles of the hand, including those that extend the interphalangeal joints of the fingers.

The radial nerve:

powers the muscles that extend the elbow, wrist, and digits. The sensation from the skin on the back of the radial side of the hand is transmitted by this nerve.

Sources Cited:

www.ivy-rose.co.uk
catalog.nucleusinc.com
www.cmki.org/ about/HWAchapter.cfm
fulton.edzone.net

2006-03-25T13:05:00.000-08:00

I STILL CAN NOT FIGURE OUT HOW TO ENLARGE THE PICTURES WITHOUT THEM BEOMING FUZZY! TO GET A BETTER VIEW OF THEM YOU CAN DOUBLE CLICK SORRY!

Overview of the Peripheral Nerves and how they fit in with the Vertebral Column and the structure of the Vertebrae

The peripheral nervous system is the portion of the verve system consisting of nerves and ganglia that lie outside of the brain and spinal cord.

The vertebral column is formed of a number of individual bones called vertebrae and two composite bones which are the sacrum and the coccyx.
The vertebral column is formed from 26 irregular bones connected in such a way that a flexible, curved structure results. It serves as the axial support of the trunk. It extends from the skull to the pelvis, where it transmits the weight of the trunk to the lower limbs.
The vertebral column consists of 33 separate bones, called vertebrae. Nine of them fuse to form two composite bones, the sacrum and the tiny coccyx. The remaining 24 bones persist as individual vertebrae separated by intervertebral discs.

Structure of the Vertebrae

All vertebrae have a common structural pattern
Each vertebrae consist of a body, or Centrum, interiorly and a vertebral
arch posterior. Together the body and vertebral arch enclose an opening called the vertebral foreman.
The vertebral arch is a composite structure formed by two laminae.
The pedicles are short bony pillars projecting posterior from the vertebral body, and form the sides of the arch.
The laminae are flattened plates that fuse in the median plane and they complete the arch posterior.
Seven processes project from the vertebral arch.

31 pairs of spinal nerves arise along the spinal cord. These are "mixed" nerves because each contain both sensory and motor axons. However, within the spinal column:

all the sensory axons pass into the dorsal root ganglion where their cell bodies are located and then on into the spinal cord itself.
all the motor axons pass into the ventral roots before uniting with the sensory axons to form the mixed nerves.
The spinal cord carries out two main functions:
It connects a large part of the peripheral nervous system to the brain.
Information (nerve impulses) reaching the spinal cord through sensory neurons are transmitted up into the brain. Signals arising in the motor areas of the brain travel back down the cord and leave in the motor neurons.
The spinal cord also acts as a minor coordinating center responsible for some simple reflexes like the withdrawal reflex.
The interneurons carrying impulses to and from specific receptors and effectors are grouped together in spinal tracts.

Sources Cited

users.rcn.com
human anatomy & physiolohy sixth edition
publish.uwo.ca
inside.salve.edu
abdellab.sunderland.ac.uk
mswatch.com
marymount.k12.ny.us
spinalinjury.net
paraquad.asn.au
octc.kctcs.edu

Tissue Feb. 10, 2006

2006-02-10T12:35:00.000-08:00

Tissue

(Pictures appear blury just double click to enlarge)

Cells group together in the body to form tissues - a collection of similar cells that group together to perform a specialized function.

Tissue Types

Epithelial Tissue
Connective Tissue
Nervous tissue
Muscle Tissue

Epithelial Tissue

The cells of epithelial tissue pack tightly together and form continuous sheets that serve as linings in different parts of the body. Epithelial tissue serve as membranes lining organs and helping to keep the body's organs separate, in place and protected. Some examples of epithelial tissue are the outer layer of the skin, the inside of the mouth and stomach, and the tissue surrounding the body's organs.

Classifications

Simple - single cell layers
Stratified - two or more cell layers

SimpleSimple Squamous Epithelia

allows the passage of materials by diffusion and filtration in sites where protection is not important
it also secretes lubricating substances in serosae
it can be found in the kidney glomeruli, in air sacs in the lungs, in the lining of the heart, in blood vessels and lymphatic vessels and in the lining of the ventral body cavity

Simple Cuboidal Epithelia
allows secretion and absorption
found in the kidney tubules and the ducts and secretory portions of small glands and also the surface of the ovaries

Simple Columnar Epithelia
allows absorption, secretions of mucus, enzymes, and others
it can be found in the lining of the stomach and anal canal, gall bladder, and some excretory ducts of some glands, and some regions of the uterus

Stratified

Stratified Squamous Epithelia
protects underlaying tissues in areas that could get hurt
found in the moist linings of the esophagus
also found in the mouth and the vagina

Stratified Cuboidal Epithelia
found maily in the ducts of sweat and mammary glands
they are rare to be found in the body

Stratified Columnar Epithelia
can be located in the male trethra and in some ducts in the glandular
Pseudostratified Columnar Epithelium
allows secretion, particularly of mucus, propulsion of mucus by ciliary action
found in just about all of the upper respiratory tract, nonciliated type's in male sperm- carrying ducts & ducts of large glands

Connective Tissue

Found everywhere in the human body
Binds & Supports
Protection
Insulation
Transportation through the blood
Most types of connective tissue contain fibrous strands of the protein collagen that add strength to connective tissue. Some examples of connective tissue include the inner layers of skin, tendons, ligaments, cartilage, bone and fat tissue. In addition to these more recognizable forms of connective tissue, blood is also considered a form of connective tissue.

Classifications

Embryonic Connective Tissue

Connective Tissue Proper

Loose Connective Tissue

Areolar
Adipose
Reticular

Dense Connective Tissue

Dense Regular
Dense Irregular

Cartilage

Hyaline : found in the embryonic skeleyon, it also covers the ends of long bones in the joint cavities, and forms costal cartilages of the ribs, nose, trachea, and larynx
Elastic: Supports the external ear, epiglottis.
Fibrocartilage: found in the intervartibral discs, discs of knee joints, and pubic symphysis.

Bone

Osseous Tissue: Found in bones

Blood

found only in blood vessels

Muscle Tissue

a specialized tissue that can contract
contains the specialized proteins actin and myosin that slide past one another and allow movement.
Examples of muscle tissue are contained in the muscles throughout your body.

Classifications

Skeletal Muscle Tissue: found in the skeletal muscles that are attached to bones and sometimes in skin
Cardiac Muscle Tissue:found in the walls of the heart
Smooth Muscle Tissue: found mainly in the walls of hollow organs

Nerve Tissue
contains two types of cells: neurons and glial cells.
has the ability to generate and conduct electrical signals in the body
electrical messages are managed by nerve tissue in the brain and transmitted down the spinal cord to the body.
Located in the brain, spinal cord, and nerves

Graphics were used from the following web sites:

Information found in Human Anatomy & Physiology Book Ed

Organization of the Human Body (not done)

2006-02-02T03:34:00.000-08:00

Overall Organization of the Human Body

Levels of Structural Organization

The levels of structural organization of the body, from simplest to most complex, are:

chemical
cellular
tissue
organ
organ system
organismal

The 11 organ systems of the body are:

integumentary system
skeletal system
muscular system
nervous system
endocrine system
cardiovascular system
lymphatic system
respiratory system
digestive system
urinary system
reproductive system
( the immune system is a functional system closely associated with the lymphatic system.)

Structural organization

The simplest level of the structural hierarchy is the chemical level. at this level, atoms combine to form molecules such as water and proteins. Molecules, in turn, associate in specific ways to form organelles. Cells are the smallest units of living things. The cellular level. All cells have some common functions, but individual cells vary widely in size and shape, reflecting their unique functions of the body.

The simplest living creatures are composed of single cells, but in complex organisms such as human beings, the hierarchy continues on to the tissue levels. Tissues are groups of similar cells that have a common function. The four basic tissue types in the human body are epithelium, muscle, connective tissue and nervous tissue. Each tissue type has a characteristic role in the body.

Epithelium: covers the body surface and lines its cavities
Muscle: provides movement
Connective tissue: supports and protects body organs
Nervous tissue: provides a means of rapid internal communication by transmitting electrical impulses.

An organ is a discrete structure composed of at least two tissue types that performs a specific function for the body. At the organ level, extremely complex functions become possible. Lets take the stomach for an example. Its lining is epithelium that produces digestive juices, the bulk of its walls is muscle, which churns and mixes stomach contents, its connective tissue reinforces the soft muscular walls, and its nerve fibers increase digestive activity by stimulating the muscle to contrast more vigorously and the glands to secrete more digestive juices. The liver, the brain, and the blood vessel are very different from the stomach, but they are organs as well. You can think of each organ of the body as a specialized functional center responsible for a necessary activity that no other organ can perform.

The next level of organizations is the organ system. Organs that work together to accomplish a common purpose make up an organ system. For example, the heart and blood vessels of the cardiovascular system see to it that blood circulates continuously to carry oxygen and nutrients to all body cells. Besides the cardiovascular system, the other organ systems of the body are the:

Integumentary
Skeletal
Muscular
Nervous
Endocrine
Respiratory
Digestive
Lymphatic
Urinary
Reproductive

The highest level of organization is the organism, the living human being. The organismal level represents the sum total of all structural levels working together to promote life.

Integument System

Forms the external body covering

Protects deeper tissues from injury
Synthesizes vitamin D

Site of cutaneous (pain, pressure, etc.) receptors

Sweat and oil glands

Skeletal System

Protects ad supports body organs

Provides a framework the muscles use to cause movement
blood cells are formed within bones
Stores minerals

Muscular System

Allows manipulation of the environment

Locomotion and facial expression

Maintains posture

Produces heat

Nervous System

Fast-acting control system of the boy

Responds to internal changes by activating appropriate muscles ad glands

Endocrine System

Glands secrets hormones that regulate processes such as growth, reproduction, and nutrient use (metabolism) by body cells

Cardiovascular System

Blood vessels transport blood which carries oxygen, carbon dioxide, nutrients, wastes, etc.

The heart pumps blood

Lymphatic System

Picks up fluid leaked from blood vessels and returns it to blood

Disposes of debris in the lymphatic stream

Houses white blood cells involved in immunity

Immune System

A functional system that protects the body via the immune responses

I which foreign substances are attacked by lymphocytes and or antibodies

Respiratory System

Keeps blood constantly supplied with oxygen and removes carbon dioxide

The gaseous exchanges occur through the walls of the air sacs of the lings

Digestive System

Breaks down food into absorbable units that enter the blood for distribution to body cells

Indigestible food stuffs are eliminated as feces

Urinary System

Eliminates nitrogenous wastes from the body

Regulates water, electrolytes, and acid-base balance of the blood

Male/Female Reproductive System

Overall function is production of offspring

Testes produce sperm and male sex hormones

Ducts and glands aid in delivery of sperm to the female reproductive tract

Ovaries produce eggs and female sex hormones

Remaining structures serve as sites for fertilization and development of the fetus

Mammary glands of female breasts produce milk to nourish the newborn

Fetal Development

The fetal period is the time of rapid growth of the body structures that were established in the embryo, during the first half of this period, cells are still differentiating into specific cell types to form the body's distinctive tissues and are completing the fine details of body structure. During the fetal period, the developing fetus grows from a crown-to-rump length of about 30mm and a weight of approximately 2g to about 360mm and 2.7-4.1 kg or more. as you might expect with such tremendous growth, the changes in fetal appearance are quite dramatic.

Intro Information

2006-01-23T07:30:00.000-08:00

Cheryl Valoroso
California/ Nov. 25, 1983
I don't have a favorite, I like just about everything.
This is a pre- requisite for the nursing program.
I have two younger sisters.

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