Introduction to Anatomy and Physiology Chapter 1 Introduction to Anatomy and Physiology

What is Anatomy? Anatomy is the branch of science that deals with the morphology (structure) of body parts. It primarily deals with the organization and form of body structures. Anatomy will tell you that this is a spine, that it is composed of osteocytes, and that it is located in the dorsal (posterior) area of most animals.

What is Physiology? Physiology is more concerned with the function of the body part. It wants to answer the questions of what does it do and how does it do it. Physiology would tell you that it acts as support and protection for the spinal cord. That the vertebrae are designed to allow for mobility while still protecting the spinal cord.

Characteristics of Life As you might imagine anatomy and physiology deals with living organisms or at least organisms that were at one point alive. Before we can continue we need to know what constitutes life. What are some of the characteristics you can think of?

Characteristic Description Movement Self initiated change in position, motion of internal parts Responsiveness Ability to sense changes and react to them Growth Increase in size Reproduction Producing new individuals Respiration Obtaining O2, using it to release energy, and removal of waste Digestion Chemically changing food substances, and waste removal Absorption Passage of digested products through membranes and into body fluids Circulation Movement of substances throughout the body Assimilation Chemically changing absorbed substances to new substances Excretion Removal of waste Metabolic Process All physical and chemical changes occurring in an organism Homeostasis Tendency of the body to maintain a stable, balanced internal environment. Accomplished through self regulating adjustments

Maintenance of Life There are five basic requirements for organisms to remain living. Water, Food, Oxygen, Heat, and Pressure. All of these are involved in processes in the body and these processes must be regulated. This is where homeostasis comes in.

Homeostasis It is the condition of a stable internal environment. It uses a set point and receptors and effectors to determine what actions to take. It is a systems that when it detects an imbalance corrects the imbalance, this is known as a negative feed back loop.

Levels of organization Going from smallest to largest, you start with an atom and end with an organism. To reach the next level you need to group the parts to gather. Lots of atoms=molecule; lots of molecules= organelle; lots of organelles= a cell; and so on.

General organization of the body It consists of two main portions. The axial portion in blue which includes the head, neck and trunk. The appendicular portion in pink which contains the arms and legs.

There are several body cavities in the body. These cavities are lined with membranes. These cavities also house a variety of organs and organ systems. This is known as viscera or visceral organs.

Body Cavities Cranial –holds the brain Spinal—holds the spine Thoracic—holds the heart, lungs, esophagus, and trachea Abdominal—holds the stomach, spleen liver, gall bladder, small intestine Pelvic—Holds part of the large intestine, urinary bladder, reproductive organs

The thoracic and abdominal cavities are separated by a muscle known as the diaphragm. Organs within the cavities are surrounded by a double layer membrane to help cushion the organs and hold them in place.

Membranes Pleura—surrounds the lungs Pericardium—surrounds the heart Peritoneum—surrounds all the organs

Organ Systems There are nine organ systems in the human body. Integumentary—Body covering. This includes skin, hair, nails, and sweat glands. It’s purpose is to protect underlying tissues and regulate body temperature.

Skeletal—Bones, ligaments, and cartilage Skeletal—Bones, ligaments, and cartilage. I provides support, movement, protection, and provides the blood cells

Muscular—muscles of the body, provides movement, maintenance of posture, and body heat.

Nervous—Brain, spinal cord, and nerves throughout the body, its function is communication throughout the body, mental activities, and maintaining homeostasis.

Endocrine—Ductless glands such as pituitary, adrenal, thyroid, parathyroid, pancreas, ovaries, testes, thymus, and pineal glands. Its purpose is secretion of hormones, and communication between body parts

Digestive—mouth, teeth, pharynx, esophagus, stomach, small intestine, large intestine, liver, gall bladder ect. Its purpose is to breakdown food into simpler forms that can be absorbed.

Circulatory—Heart, blood vessels, and blood Circulatory—Heart, blood vessels, and blood. It transports materials throughout the body. *The lymphatic system is usually included with the circulatory system since they use the same path ways.*

Urinary—Kidneys, ureters, urinary bladder, and urethra Urinary—Kidneys, ureters, urinary bladder, and urethra. It removes (“filters”) wastes from the body and helps maintain the body’s water and electrolyte balance.

Reproductive—Reproductive organs (primarily the ovaries and testes) Reproductive—Reproductive organs (primarily the ovaries and testes). Its purpose is to produce reproductive cells to allow for reproduction.

Anatomical Terminology The official anatomical position is : Standing erect, face forward, arms at side, palms facing forward. All descriptions of placement are based on this position and are relative positions, meaning they are dependent on the placement of other objects.

Superior—a body part is above another part or closer to the head. Ex: The thoracic cavity is superior the abdominopelvic cavity.

Inferior—body part is below another body part or towards the feet. Ex: The neck is inferior to the head.

Anterior (ventral)—Towards the front Ex: The eyes are anterior to the brain.

Posterior (dorsal)—Towards the back. Ex: The pharynx is posterior to the oral cavity

Medial—an imaginary line that divides the body into equal right and left halves. A body part is medial when it is closer to this center line than another body part. Ex: The nose is medial to the eyes.

Lateral—means towards the side with respect to the imaginary line. Ex: The ears are lateral to the eyes

Proximal—Describes a body part closer to a point of attachment to the trunk than another body part. Ex: The elbow is proximal to the wrist.

Distal—describes a body part that is farther away from the trunk. Ex: The fingers are distal to the wrist

Superficial—situated near the surface. Ex: The epidermis is the superficial layer of skin.

Deep—describes parts that are more internal compared to a superficial part. Ex: The dermis is the deep layer of skin.

Body Regions Sagittal—refers to a length wise plane that divides the body into left and right portions.

Transverse (horizontal)—refers to a plane that divides the body into superior and inferior portions.

Frontal (coronal)—refers to a plane that divides the body into anterior and posterior positions.