Overview

The concepts in this chapter will orient you to the human body and introduce you to the science of anatomy. Mastering the vocabulary in this chapter will help you to understand basic anatomical relationships and help you to communicate effectively with anatomists and those working in the healthcare professions.

Use the items under Additional Resources to help you form a firm grasp of the material.

Learning Objectives

At the end of this lecture, you will be able to...

Define anatomy and physiology, and describe the subdisciplines of anatomy.
Use the meaning of word roots to aid in understanding anatomical terminology.
Identify the levels of structural organization in the human body, and explain the interrelationships between each level.
List the organ systems of the body, and briefly state the functions.
Use metric units to quantify the dimensions of cells, tissues, and organs.
Define anatomical position.
Use anatomical terminology to describe body directions, regions, and planes.
Locate the major body cavities and their subdivisions.
Name the four quadrants of the abdomen, and identify the visceral organs located within each quadrant.

Lecture Notes & Slides

Lec.1 Introduction to Human Anatomy

Reading — Chapter 1 - The Human Body: An Orientation, Pages 1-13

An Overview of Anatomy (pp. 2–6)

Anatomy — The study of the structure of the human body
Physiology — The study of body function

Subdisciplines of Anatomy (p. 2)

Gross anatomy — studies the human body structures with the naked eye, and dissection is the major technique.
- systemic anatomy — organs with related functions are studied together.
- regional approach — All organs and structures in a single region are studied as a group.
Microscopic anatomy (histology & cytology) — uses the microscope to study prepared tissue slides.

The Hierarchy of Structural Organization (pp. 2-6, Figs. 1.1, 1.2)

Structural Organization (pp. 2–6)
- The levels of structural organization, from the simplest to the most complex, are listed in Figure 1.1 and the table below.

Figure 1.1	Recognizing connections between structural levels leads to better understanding of organismal function
Chemical Level	Atoms combine to form molecules. Molecules combine to form the macromolecules (carbohydrates, lipids, proteins, and nucleic acids).
Cellular Level	Cells and their surroundings are made up of molecules. For example, a phospholipid molecule is a structural component of the plasma membrane.
Tissue level	Tissues consist of similar types of cells and associated extracellular material. In this example, epithelial tissue forms the inner lining of blood vessels.
Organ level	An organ is a discrete structure made up of multiple tissue types. Examples include blood vessels, the liver, brain, and femur.
Organ system level	An organ system is a unified group of organs and tissues that perform a specific function. The example shown here is the cardiovascular system, showing blood vessels, blood, and the heart.
Organismal level	The whole person is the most complex level of organization, the organismal level, resulting from the simpler levels working interdependently.

Organ systems are organs working closely together to accomplish a common function. The body’s organ systems are shown in Figure 1.2 (p.4) and the table below.

Figure 1.2 The Body's organ systems & their major functions

Figure 1.2	The body’s organ systems and their major functions
Integumentary system	Forms the external body covering and protects deeper tissues from injury. Synthesizes vitamin D and houses cutaneous receptors (pain, pressure, etc.) and sweat and oil glands.
Skeletal system	Protects and supports body organs and provides a framework the muscles use to cause movement. Blood cells are formed within bones. Bones store minerals.
Muscular system	Allows manipulation of the environment, locomotion, and facial expression. Maintains posture and produces heat.
Nervous system	As the fast-acting control system of the body, it responds to internal and external changes by activating appropriate muscles and glands.
Endocrine system	Glands secrete 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/ Immune System	Picks up fluid leaked from blood vessels and returns it to blood. Disposes of debris in the lymphatic stream. Houses white blood cells (lymphocytes) involved in immunity. The immune response mounts the attack against foreign substances within the body.
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 lungs.
Digestive System	Breaks down food into absorbable units that enter the blood for distribution to body cells. Indigestible foodstuffs are eliminated as feces.
Urinary System	Eliminates nitrogenous wastes from the body. Regulates water, electrolyte, and acid-base balance of the blood.
Reproductive System	Overall function is production of offspring. Testes produce sperm and male sex hormone, and male ducts and glands aid in delivery of sperm to the female reproductive tract. Ovaries produce eggs and female sex hormones. The remaining female structures serve as sites for fertilization and development of the fetus. Mammary glands of female breasts produce milk to nourish the newborn.

Scale: Length, Volume, and Weight (p. 6)

The metric system provides precision for measuring the dimensions of cells, tissues, and organs.

Anatomical Terminology (p. 6)

Ancient Greek and Latin provide the origins for most anatomical terms.

Gross Anatomy: An Introduction (pp. 6–13)

The Anatomical Position (p. 6)

a common visual reference point
Learning the anatomical position is essential because directional terminology used in anatomy refers to the body in this position.
To accurately describe the various body parts and their locations, you need to use a common visual reference point. This reference point is the anatomical position (Figure 1.3a).
In this position, a person stands erect with feet flat on the ground, toes pointing forward, and eyes facing forward. The palms face anteriorly with the thumbs pointed away from the body.
Additionally, the terms right and left always refer to those sides belonging to the person or cadaver being viewed—not to the right and left sides of the viewer.

Regional Terms (p. 6)

absolute and name the specific body areas. (Figure 1.3)
2 fundamental regions — axial and appendicular — divided into smaller regions

Abdominal	Anterior body trunk region inferior to the ribs	Mental	Chin
Acromial	Point of the shoulder	Nasal	Nose
Antebrachial	Forearm	Occipital	Posterior aspect of the head or base of the skull
Antecubital	Anterior surface of the elbow	Olecranal	Posterior aspect of the elbow
Axillary	Armpit	Oral	Mouth
Brachial	Arm	Orbital	Bony eye socket (orbit)
Buccal	Cheek	Otic	Ear
Calcaneal	Heel of the foot	Palmar	Palm of the hand
Carpal	Wrist	Patellar	Anterior knee (kneecap) region
Cephalic	Head	Pedal	Foot
Cervical	Neck region	Pelvic	Pelvis region
Coxal	Hip	Plantar	Sole of the foot
Crural	Leg	Pollex	Thumb
Digital	Fingers or toes	Popliteal	Back of the knee
Dorsal	Back	Pubic	Genital region
Femoral	Thigh	Sacral	Region between the hips (overlying the sacrum)
Fibular (peroneal)	Side of the leg	Scapular	Scapula or shoulder blade area
Frontal	Forehead	Sternal	Region of the breastbone
Gluteal	Buttocks or rump	Sural	Calf or posterior surface of the leg
Hallux	Great toe	Tarsal	Ankle
Inguinal	Groin area	Thoracic	Chest
Lumbar	Area of the back between the ribs and hips	Umbilical	Navel
Mammary	Breast region	Vertebral	Area of the spinal column
Manus	Hand

Figure 1.3 Anatomical position & regional terms

Directional Terms

relative and describe location of one body part in relation to another. (Table 1.1)

Table 1.1	Orientation and Directional Terms
Superior	Toward the head end or upper part of a structure or the body; above
Inferior	Away from the head end or toward the lower part of a structure or the body; below
Medial	Toward or at the midline of the body; on the inner side of
Lateral	Away from the midline of the body; on the outer side of
Proximal	Closer to the origin of the body part or the point of attachment of a limb to the body trunk
Distal	Farther from the origin of a body part or the point of attachment of a limb to the body trunk
Ipsilateral	On the same side
Contralateral	On opposite sides
Unilateral	On one side of the body
Bilateral	On both sides of the body
Anterior (ventral)*	Toward or at the front of the body; in front of
Posterior (dorsal)*	Toward or at the back of the body; behind
Superficial (external)	Toward or at the body surface
Deep (internal)	Away from the body surface; more internal

*Whereas the terms ventral and anterior are synonymous in humans, this is not the case in four-legged animals. Ventral specifically refers to the “belly” of a vertebrate animal and thus is the inferior surface of four-legged animals. Likewise, although the dorsal and posterior surfaces are the same in humans, the term dorsal specifically refers to an animal's back. Thus, the dorsal surface of four-legged animals is their superior surface.

Body Planes and Sections (pp. 7 and 10, Fig. 1.4)

The body and/or organs are cut into sections along a flat surface called a plane.
- Frontal (coronal) plane — divides body into anterior and posterior parts.
  - If equal halves — mid-coronal
- Transverse (horizontal) plane —divides body into superior and inferior parts
- Sagittal planes — Divide body into right and left parts
  - Median (midsagittal) plane — Sagittal plane that runs along the midline
  - Parasagittal planes — A sagittal plane offset from the midline

Body Cavities and Membranes (pp. 11–13, Figs. 1.6, 1.7)

Dorsal body cavity is subdivided into:
- cranial cavity — houses the brain.
- vertebral cavity — runs through the vertebral column and encloses the spinal cord.
Ventral body cavity
- Contains the visceral organs (viscera) — e.g. lungs, heart, intestines, kidneys, etc.
- 2 main divisions – thoracic and abdominopelvic cavities, separated by the diaphragm (a dom shaped muscle used in breathing)
- Thoracic cavity – 2 lateral parts (pleural cavities) plus a central part (mediastinum)
  - Pleural cavities– containing the lungs
  - Mediastinum
    - contains the heart surrounded by a pericardial cavity (“around the heart”) and pericardial sac
    - also houses other major thoracic organs, such as the esophagus and trachea (windpipe).
  - Abdominopelvic cavity—divided into the abdominal and pelvic cavities, which are continuous with one another and not separated by any muscular or membranous partition. Many organs in the abdominopelvic cavity are surrounded by a peritoneal cavity.
    - Abdominal cavity—contains digestive organs (liver, stomach, intestines, etc), kidneys, more
    - Pelvic cavity—contains the bladder, some reproductive organs, and rectum

Serous cavities — Three serous cavities are all enclosed body cavities with no openings to the external surface of the body. Each of these is a potential space lined by a serous membrane (serosa)
- - Pleural cavities— lined by pleura; each surrounding a lung
  - Pericardial cavity — lined by pericardium; surrounds the heart
  - Peritoneal cavity — lined by peritoneum; surround the abdominopelvic viscera
- Each of these serosa consist of 2 layers
  - - Parietal layer — forms the outer wall of the cavity
    - Visceral layer — Covers the visceral organ(s) inside the cavity
  - Parietal and visceral layers are continuous with one another. The potential space enclosed within is the serous cavity – pleural, pericardial, and peritoneal cavities.
- Contain a small amount of serous fluid produced by both layers of the serous membranes

Abdominopelvic Quadrants & Regions (pp. 13)

Because the abdominopelvic cavity is quite large and contains many organs, it is helpful to divide it up into smaller areas for discussion or study.
Can be divided into 4 quadrants (Figure 1.8a) or 9 regions

Microscopic Anatomy: An Introduction (pp. 13–15)

Microscopy is the examination of the fine structure of organs, tissues, and cells.

Lecture video

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