HUMAN ANATOMY is the study of the structures of the human body. Physiology is the function of anatomical structures of the body. It is important for people in the emergency medical field to have a working knowledge of the human body and its systems for appropriate care and to communicate with patients.
DIRECTIONAL TERMS
The relative position of body structures is communicated through the use of directional terms. Directional terms are typically words grouped in pairs, with the terms in each pair having opposite meanings. Directional terms can apply to organs or the body as a whole, such as:
- Anterior is toward the front or abdominal surface of the body
- Posterior is toward the back of the body
- Superior is toward the head.
- Inferior is away from the head
- Medial is nearer the midline of the body
- Lateral is farther from the midline.
- External is toward or on the body surface.
- Internal is away from the body surface.
Anatomical Position
When directional terms are used, it is assumed that the body is
in a standard position. An anatomical position is a situation in
which the body is erect with arms at the sides and the palms of
hands facing forward.
Organization of the Body
The human body is composed on multiple organizational levels, from simplest to most
complex. Components of each level work together to maintain homeostasis—the relative
constancy of the body’s internal environment. The organizational levels (from smallest to largest) are cell, tissue, organ, organ system, and organism.
ORGAN SYSTEMS
Most of the functions of the body are performed by organ systems. An organ is a structure
composed of two or more tissues that has a definite shape and performs specific functions. An
organ system is a group of organs that work together to perform functions. Eleven organ
systems are found in the human body
Integumentary System
The skin (including hair, nails, glands, and sensory receptors) make up the integumentary
system
Skeletal System
The skeletal system is the framework of the body and provides support and protection
for softer organs. It consists of bones, cartilages, and ligaments.
Muscular System
The muscular system is skeletal muscles and tendons that contract to provide the force
for movement.
Nervous System
The nervous system is a complex, highly organized system containing the brain, spinal
cord, cranial and spinal nerves, and sensory receptors. These organs work together to rapidly
perceive and interpret the environment while coordinating bodily functions. The human brain
is responsible for intelligence, will, self-awareness, and emotions.
Endocrine System
The endocrine system is small masses of tissue that secrete hormones absorbed by the
blood and transported throughout the body where they bring about chemical control of body
functions.
Cardiovascular System
The heart, arteries, veins, capillaries, spleen, and blood make up the cardiovascular system.
These organs work to transport materials (e.g., oxygen, carbon dioxide, nutrients, wastes, and
hormones) throughout the body.
Lymphatic System
The lymphatic system is made of lymph tissue and vessels that collect fluid between cells and
return it to large veins. Lymph passes through lymph nodes that remove debris and bacteria.
Respiratory System
The respiratory system is the system where the exchange of oxygen and carbon dioxide
between the atmosphere and blood takes place. Air passages and gas-exchange organs make it
possible.
Digestive System
The digestive system is a system that converts large food particles into smaller nutrient
particles that can be absorbed into the blood. Digestion involves mechanically breaking food
into smaller particles and mixing them with digestive fluids.
Urinary System
The kidneys of the urinary system remove wastes and excess water from the blood and body
through urine.
Reproductive System
The reproductive system sustains the existence of the human species. Organs vary in the
male and female reproductive systems. For example, males have testes that produce sperm, and
females have ovaries that release eggs
The human body is composed on multiple organizational levels, from simplest to
most complex. Components of each level work together to maintain homeostasis—the relative constancy of the body’s internal environment. The organizational
levels (from smallest to largest) are cell, tissue, organ, organ system, and organism.
Most of the functions of the body are performed by organ systems. An organ is a
structure composed of two or more tissues that has a definite shape and performs
specific functions. An organ system is a group of organs that work together to perform functions. The organ systems in the human body are integumentary, skeletal,
muscular, nervous, endocrine, cardiovascular, lymphatic, respiratory, digestive, urinary, and reproductive.