Week 1 Concepts

Anatomy is the study of body structure(s), morphology, and the relationships of its parts. It pertains to an identified location, number, and orientation of a particular body part.​

​Anatomy is naming structures by looking at:​

• location ​

• structure and morphology (the science of form and shape) ​

• relationships among body parts ​

​There are two approaches to studying anatomy.​

• Microscopic anatomy requires the use of a microscope. For example, cytology is the study of cells and histology is the study of tissues.​

• Macroscopic (or gross) anatomy is the study of anatomy with the naked eye.​

Physiology is the study of the function of body parts and how they interact with one another. Physiology answers questions that inquire about how mechanisms occur.

Pectus excavatum is a great example of how a problem with structure can affect function, and vice versa. ​

• Pectus excavatum is a congenital anatomical anomaly involving the thoracic cage (rib cage) giving the chest a "sunken in" appearance.​

• These patients often complain of dyspnea (discomfort while breathing).

The core concept, "complementarity of structure & function" is the principle that states, function is highly dependent on structure, and that the arrangement of structure directly influences function; i.e., structure determines function.

We have a saying in A&P: "Structure mimics function". Remembering this will help you to understand that when you change a structure, you can then also change its function.

Anatomically, the thoracic cage, and thus the lungs, must expand during inspiration for oxygen to be inhaled into the lungs.​

Physiologically, a structural deformity of the thoracic cage prevents this expansion from occurring during inspiration, resulting in dyspnea.

Unity of Structure and Function

Red blood cells are a great example of the unity of structure and function.​

• The primary function of red blood cells (RBC) is to transport oxygen (O2) to the tissues and carbon dioxide (CO2) from the tissues to the lungs so that it can be exhaled out of the body.​

• A mature red blood cell is shaped like a round biconcave disk, somewhat like a donut (but without the hole in the middle). This maximizes surface area, which in turn, maximizes oxygen carrying capacity.​

• The loss of the typical round, biconcave disk morphology of a red blood cell (RBC) will have an impact on its ability to transport gases such as oxygen and carbon dioxide.​

• Sickle cell anemia is a genetic condition that causes crescent or “sickle” shaped RBC’s, impairing their ability to perform their normal function of transporting gases. 

Recall the principle of Complementarity of Structure and Function: structure determines function.

Anatomical Position and Anatomical Terminology

Anatomical position is the standard frame of reference used in all anatomical descriptions to ensure accuracy and consistency.​

• Most, if not all, illustrations show the human body in the “anatomical position”.​

• Acts as a reference point for all directions and regions of the human body.​

• In the anatomical position, the patient is: ​

  • Standing erect​

  • Body is upright​

  • Head facing forwards ​

  • Arms at the side​

  • Palms of the hands facing forwards​

  • Lower limbs parallel​

  • Feet together feet flat on the floor​

  • Toes directed forward

Generally, most illustrations are shown in the "anatomical position", structures on the left side of the body are shown on the right side of the page, and structures on the right side of the body are shown on the left side of the page.

Sometimes, in medical terminology, we will use more than one word to mean the same thing. Here are some examples of that in directional terminology of the body.​

​Ventral: ​

• Refers to the front of the organ/body.​

• Ventral: Belly side of the body; -al: pertaining to.​

Anterior​:

• Situated in the front​

• Anter: front or before; -ior: pertaining to.

​Dorsal: ​

• Refers to the back of the organ/body.​

• Dors: back of the body; -al: pertaining to. ​

​Posterior​:

• Situated in the back​

• Poster: back or toward the back; -ior: pertaining to.​

Directional terms are used to describe one body part in relation to another. The point of reference for all directional terms is the anatomic position. ​

​Anatomical Terms of Direction:​

• Anterior or Ventral means front or belly side.​

• Posterior or Dorsal means back side.​

• Superior is close to the top of the head and is used for the axial region only.​

• Inferior is farther away from the top of the head and is used for the axial region only. ​

• Medial is toward the midline of the body.​

• Lateral is away from the midline of the body.​

• Supine is lying on the back, face up. ​

• Prone is lying on the abdomen, face down. ​

• Proximal is closer to the connection to the body and is used for the appendicular region only.​

• Distal is farther from the connection to the body and is used for the appendicular region only.​

• Superficial is close to the surface.​

• Deep is farther from the surface.​

• Right is on the body's right side​.

• Left is on the body's left side. 

Anatomical Terms: Afferent and Efferent

The terms afferent and efferent refer to the direction of flow relative to a reference point. ​

• Afferent flow is flow toward a reference point.​

  • Example: Venous blood flow is afferent to the heart​.

  • Remember: A for Accepting

• Efferent is a flow away from a reference.

  • ​Example: Arterial blood flow is efferent to the heart.​

  • Remember: E for Exiting

Anatomical Terms: Spatial Relationships

It is important to emphasis that the terms "anterior" and "posterior" describe the spatial relationship between two anatomical structures.​

• ​In the context of hand anatomy, the terms "palmar" and "dorsal" denote the surfaces corresponding to the anterior and posterior aspects, respectively. ​

  • Palmar is a directional term that refers to the surface of the hands that contains the digits with fingerprints.​

  • Dorsal is the directional term referring to the back of the hand.

• ​The term "plantar surface" is used to designate the sole of the foot, while the term "dorsal surface" is employed to denote the upper surface of the foot.

Directional Terms

Imagine the middle of your body has this imaginary line drawn straight down the middle. We will use this imaginary line to better understand these next directional terms. ​

​Lateral: Towards or nearer the side of the body, away from the midline.​

• Example: The arms are lateral to the chest​

​Medial: Toward, or nearer, to the midline.​

• Example: The chest is medial to the arms

Some directional terms are only used when referencing a specific part of the body. For example, the terms listed below are only used when talking about the upper and lower extremities.​

​Proximal: Closer to the point of attachment. ​

• Location in either the upper limb or lower limb close to the trunk of the body.​

• Example: The shoulder is proximal to the elbow.​

​Distal: Farther from the point of attachment. ​

• Location in either the upper limb or lower limb farther away from the trunk of the body​.

• Example: The fingers are distal to the elbow.

Directional Terms: Caudal and Cephalad

Caudal: Caud/o = tail or tailbone. ​

• Down toward the bottom of a structure, below.​

• Example: The hips are caudal to the waist. ​

Cephalad: Cephal/o = head, ad = toward.​

• Toward the direction of the head, above.​

• For example, the cephalad direction is upwards because that is where the head is located.

Directional Terms: Superficial and Deep

Superficial: Closer to the surface.​

• Example: The skin is superficial to the body’s internal organs and underlying structures​.

Deep: Farthest from the surface.​

• Example: The bone of the upper arm is deep into the surrounding muscle.

Recap: Anatomical Position and Terminology

The breast is ______to the buttocks​; Anterior

The lumbar region is ______to the breast; Posterior

The elbow is ______to the fingers; Proximal (closer to point of attachment to the body)

The elbow_____ to the wrist; Proximal

In the anatomical position, the head is facing; forward

____ is a directional term that refers to the surface of the hands that contains the digits with fingerprints; Palmar

The nose is _______ to the eyes; Medial

Regional Anatomy

Anatomical regions:​

• A region refers to a particular area of the body.​

  • Two major regions of the body:​

    • Axial

      • Represents the core of the body​.

      • Includes structures that are located in the center of the body or down the body’s axis.

      • Includes all body structures except the upper and lower appendages.

    • Appendicular​

      • ​​Includes the upper and lower appendages (arms and legs).

Regional anatomy is the study of the body's structure by region (head, abdomen, etc.).

• A region, like a map, refers to a specific area. ​We often refer to structures of the body depending on what region they are found in.

  • For example, the digestive organs are found in the abdominal region.

​In the subsequent section, we will examine the classification of region terms based on their respective locations, specifically within the axial or appendicular regions.

Regional Terms: Axial and Appendicular Region

Cranium (Skull)

• Cephalic – head​

• Frontal – forehead​

• Temporal – temples, or sides of the skull behind the eye socks.​

• Occipital – back of the head​

• Orbital/Ophthalmic – eyes​

• Otic/Auricular – ears​

• Nasal – nose​

• Facial – face​

• Buccal – cheek​

• Oral – mouth​

• Maxillae – the upper jaw​

• Mandible – the lower jaw​

• Mental – chin 

Cervical

• Cervical – neck​

• Nuchal – nape (back of the neck)

Trunk (Thorax & Abdominopelvic Regions)

• Thoracic – chest cavity​

• Pectoral – chest​

• Mammary – breast ​

• Pericardial – heart ​

• Costal – ribs​

• Sternal – breastbone​

• Umbilical – navel (belly button)​

• Abdomen – part of the body between thorax & pelvis​

• Coxel – hip​

• Pelvis – cavity below the abdomen containing reproductive organs.​

• Inguinal – groin​

• Lumbar – lower back​

• Sacral – areas between the hips​

• Perineal – between anus and external genitalis 

Upper Limb

• Axillary – armpit​

• Brachial – upper arm (arm)​

• Antecubital – front of the elbow​

• Olecranal – back of the elbow​

• Antebrachial – forearm (lower arm)​

• Carpal – wrist​

• Manus – hand​

• Palmar – front surface of the hand​

• Dorsum – back surface of the hand​

• Digitial or phalangeal – fingers​

• Thumb – pollux 

Lower Limb

• Gluteal – buttock​

• Femoral – thigh​

• Crural – leg (shin bone)​

• Patella – front of the knee​

• Popliteal – behind the knee​

• Surel – calf​

• Calcaneal – heel​

• Tarsal – ankle​

• Plantar – sole of the foot ​

• Dorsum – top of the foot​

• Big toe – hallux

Which is an example of anatomy?; The human heart is composed of four chambers.

Which is an example of physiology?; The valves of the human heart prevent any potential backflow of blood.

Sickle cell anemia is an example of an abnormality with?; Anatomy and Physiology 

A microbiologist studying unicellular pathogens like bacteria by using a microscopic is an example of; Cytology

A cardiothoracic surgeon performing open heart surgery must have knowledge of __________; Gross anatomy

If one is standing in the anatomical position, which of the following apply? Select all that apply; Back refers to dorsal, Back refers to posterior, Front refers to anterior, Front refers to Ventral

The elbow is ____ to wrist; Proximal

Which of the following body regions corresponds to the arm?; 

Cervical: neck​

Femoral: thigh ​

Brachial: upper arm ​

Pedal: foot​

Cephalon: head