Human anatomyHuman anatomy

Chapter 1Chapter 1

Introduction to Human Introduction to Human AnatomyAnatomy

I. Introduction to Anatomy- A broad field of science in which the body is studied at different levels. The definition of anatomy (morphology) is the study of human body or science of  form; physiology is the study of body function. As you study this subject pay attention to the theme of how "Structure Determines Function" .

• II Anatomical Terminology- The study of anatomy will introduce you to a large vocabulary.  It is as if you were learning a new language and mastery of this language is essential for your success in this class.

A. Pay attention to Greek and Latin roots as you learn the new vocabulary.  At one point Latin was the official language used in science and thus it remains today as a way to maintain consistency worldwide.

B. As you learn this new language it is recommended that you create vocabulary flash

cards pertaining to each chapter to learn the correct spelling and pronunciation (internet glossary) for each word. Practice the new vocabulary

consistently and recognize that many different words can be used to describe the same thing

III.  Branches of Anatomy- The different levels of organization that make up the body allow for the study of anatomy in various branches.

Levels of organization:Atoms form molecules          molecules form organelles (essential for cell function) 

organelles form cells

a group of cells with the same structure and function forms a tissue            

two or more different tissues form an organ two or more organs form organ systems            multiple systems form the human body.

B. Anatomy can be studied at each level of organization: 1) Gross Anatomy 2) microscopic anatomy

3)clinical anatomy4)Developmental Anatomy5) Embryology6)Functional Morphology (physiology)

1. Gross Anatomy- This form of study focuses on large body structures that can be analyzed by the naked eye, primarily through dissection. Studying the organs can be done as part of regional anatomy (all the organs in a body region) or systemic anatomy (all organs relating to one system). Surface anatomy is the study or superficial body "landmarks" that reveal underlying organs.

A. The anatomical position- A stance or position  commonly used for visual reference points.

B. Defined as standing erect, feet together and eyes, feet, and palms facing forward.

B. Directional and Regional terms- These are standard terms based on the anatomical position to precisely describe the location of a certain body part in relation to another.

i.  Directional terms are usually paired as:    superior and inferior        anterior and posterior       medial and lateral         intermediate      distal and proximal  superficial and deep. 

ADD: VENTRAL/DORSAL

See page 6 table 1.4 for definition and description.

Note-- four legged animals have a different anatomical position than humans. Thus, their ventral is on the inferior side and dorsal in on the superior side whereas in humans ventral and anterior is the same and so is dorsal and posterior

ii.  Regional terms are used to describe certain body regions, many anatomical structures will have names relating to their body region. See p 7

C. Body planes and sections- a plane is a flat sectional cut along the body (see page 11). There are four planes: 

Frontal (coronal)                              

Median (midline or sagittal)

                               Transverse (horizontal)

                                Oblique (diagonal)

• STOP FOR TODAY

D. Body cavities and membranes- cavities are spaces in the body that are filled with organs and these organs are often surrounded by membranes

i. Dorsal body cavity- a large cavity on the posterior side of the body, it contains the brain and spinal cord. It is further divided into the cranial and vertebral cavity

ii.  Ventral body cavity- another large cavity that encloses organs on the anterior side of the body. It is also divided into the   throracic cavity- divided into pleural cavity, mediastinum, and pericardial cavity abdominopelvic cavity- abdominal and pelvic cavity containing organs in peritoneal cavities

iii. Other smaller cavities may be created by membranes and are also closed to the environment

(a) Synovial cavities- formed by fibrous layers they surround joints and create lubricating fluids to reduce friction

(b) Serous cavities- formed by serous membranes (sora) that surround organs and contain two membrane layers (see page 15)

                1.parietal serosa- membrane layer that forms the outer

part of the cavity

2.visceral serosa- membrane layer that forms the inner part of the cavity and is closer to the organ (viscera)

iiii. Some cavities are smaller and open to the outside environment:  nasal, oral, orbital (eye), ear cavities (see page 16).

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E. Body quadrants and regions. To facility its study, the abdominopelvic region can also be divided into different regions and quadrants. There are four quadrants and nine regions. See page 17 and master this vocabulary, it is essential for those going into the health professions.

 

2. Microscopic Anatomy- This form of anatomy is better known as histology which is the study of tissues. Specializes cells form different types of tissues. Thus different tissues do not look or function in the same way.  Any illness or physiological problems experienced in the body occur at the cellular level.

A. Light and electron microscopy-  Two types of microscopes are used to study tissues and each reveals different aspects. Light microscopes have less magnification then electron microscopes but show color and texture. Specimens can be stained to show only certain aspects.   Electron microscopes can magnify an image to show finer detail than an electron microscope but is flat and colorless. Scanning and transmission electron microscopes a power and used to reveal more detail.

B. Preparing Human Tissue for microscopy- Tissues are processed before viewing, first they are fixed (preserved), then sectioned (thinly sliced), and then stained (color stains or metals added). The type of stain used depends on the type of microscope through which specimen will be studied.

C. Scanning Electron Microscopy-  This type of microscope uses electrons to scan the surface of a specimen  with an electron beam and create a three dimensional picture. The specimen is preserved and stain with metal, but it is not sectioned. These images are originally in shades of gray  but can be artificially colored.

   D. Artifacts- As you study specimen under the microscope or by an

unaided eye, you will notice that the structure my not strictly represent that of a living structure. Preserving and staining the specimens alters the tissues and may even create artifacts (distortions).  As your eye is trained to recognizes structures you will be able to distinguish the differences between preserved and live speicimens.

3. Clinical Anatomy- includes pathological anatomy (study of anatomical changes caused by disease) and radiographic anatomy (study of body structures by different forms of radiation). Clinical anatomy relies on different imaging techniques used for diagnosis.

A. X Rays- this is the traditional method of diagnosis.  X-rays that are directed to the body may penetrate and create a dark image if they pass through soft tissues, while those that are absorbed by dense tissues, such as bones, leave a white image. Contrast medium (solution containing heavy elements like barium) can be used to view soft tissue organs.

1. Cineradiography is a techniques in which a fluoroscope (fluorescent screen) is used to view an X-ray image as organs are moving. 

2. Prolonged exposure to X-rays can cause genetic defects, tissue damage, or cancer. Other disadvantages are: it is difficult to see soft tissues, a 3D body becomes a flatten image, denser organs block imaging of less dense organs

B. Advanced X-Ray Technique- these techniques incorporate the use of computers for processing the x-rays taken and adding color to the images.

1.CT Scan (computed tomography) or CAT Scan (computed axial tomography)- A rotating tube and recorder move around the person as X-rays are taken. A computer processes the images to create a single transverse image that reveals all organs at their best angles with almost no blocking structures.

1.CT Scan (computed tomography) or CAT Scan (computed axial tomography)- A rotating tube and recorder move around the person as X-rays are taken. A

computer processes the images to create a single transverse image that reveals all organs at their best angles with almost no blocking structures.

2. DSR (dynamic spatial resolution)- ultra fast CT scanner are used to assemble a series of CT pictures and create a three dimensional image can also be used to view in detail an organ in motion (beating heart, blood flow) 

  3. Xenon CT- a CT taken in combination with inhaled xenon (inert gas). Absence of xenon in the picture indicates area with blood flow is lacking. Used primarily for identifying an area of a stroke.

C. DSA (digital subtraction angiography)- An image is taken before and after the patient is given a contrast medium. The computer processes the x-ray images and subtracts the differences in the "before" image from the "after" image. This any blockages in blood vessels are

revealed. 

D. PET ( Positron Emission Tomography)- radioactive isotopes are detected, these isotopes may be used to follow the flow of blood to the brain  and heart. As the isotope decays it emits a gamma ray that is detected. There will be a greater concentration in areas that are more active or are receiving more blood.  Because of its cause and other limitations it is being replaced with the MRI.

 

• E. Sonography (ultra sound)- high frequency (ultrasonic) sound waves are sent through the tissues and can reflect (echo) off the body. The echo is processed by the computer to produce an image.  The equipment is inexpensive, the technique is safer, and it can be used to detect developing fetuses. Ultrasound is used to study soft tissue and contrasting mediums can also used to create better images.

F. MRI (Magnetic Resonance Imaging)-   The patient lies in a chamber surrounded by a large magnet and is exposed to a strong magnetic field when magnet is activated. Then the hydrogen atoms  in the body's water align with the magnet and a radio frequency is emitted to misalign them. As they realign with the magnet a radio wave is emitted from them. Sensors detect the waves and the computer takes these signals and produces detailed images of soft tissues. Tissues can be distinguished on the basis of their water content. Bones to do not block the view of an MRI because they have low water content.

F. MRI (Magnetic Resonance Imaging)-   The patient lies in a chamber surrounded by a large magnet and is exposed to a strong magnetic field when magnet is activated. Then the hydrogen atoms  in the body's water align with the magnet and a radio frequency is emitted to misalign them. As they realign with the magnet a radio wave is emitted from them. Sensors detect the waves and the computer takes these signals and produces detailed images of soft tissues. Tissues can be distinguished on the basis of their water content. Bones to do not block the view of an MRI because they have low water content.

4. Developmental Anatomy- focuses on the changes in body structures as the body ages and grows.

 5. Embryology- the study of organ formation and development before

birth. 6. Functional morphology- studying the function of body structures and

their design efficiency- can be related to kinesiology.

IV.  The Metric System- In the science field length, volume, and weight are measured in unit used by the metric system. This allows consistency in measurement throughout the world.  Reference Appendix A for these measurements and prefixes.

Length is measured in kilometer, meter, centimeter, or millimeter

Volume is measured in kiloliter, liter, or milliliter

Weight is measured in kilogram, gram, or milligram.

V.  Anatomical Variability- Be aware that the structures presented in the book are largely representative of  those found in every individual. However, because of our genetic diversity every individual is got structurally identical and sensory organs do not perceive the environment the same either.