Anatomy & Physiology = study of characteristics

Common Characteristics Of Living Things:

1. Organization: pattern that differs from environment, involves regulation of internal conditions within limits

2. Responsiveness: (irritability), responding to changes in environment. Adaptation = long term response

3. Growth and Differentiation Growth = increase in size/cell number Differentiation = specialization of cells to perform particular functions

4. Reproduction

5. Movement Internal Transport substances in body External move around environment

6. Metabolism and Excretion Metabolism = all chemical processes in the body (building and breaking molecules)

Form Follows Function: the shape of a structure is related to its use

Anatomy = study of internal and external structures of body and their relationships to each other: Form

Gross Anatomy = macroscopic, see by eye

Microscopic Anatomy = cell and molecule level, need microscope

Cytology = study of cells

Histology = study of tissues (groups of specialized cells that work together to perform functions)

Physiology = study of how organism perform functions: (Function)

Human Anatomy and Physiology = the study of the form and function of the human body

-understanding physiology requires a knowledge of anatomy and physics (chemistry), to explain how the heart works, how we breathe, how we regulate blood glucose…

The pattern of organization at the lower levels determines both the characteristics and functions at the higher levels.

Principle of Complementarity

•The anatomy of a part of the body reflects the physiology of that part

form determines function-

-all the parts of the body are designed to create an extremely efficient and effective machine

Homeostasis

Homeostasis is the ability to maintain a relatively constant internal environment = unchanging sameness

•For the body to work as efficiently as possible, there are hundreds of variables that must remain relatively constant (at a set point) - essential to life

–body temperature, blood glucose levels, blood pressure, body CO2 levels, body pH…

–these variables are constantly changing

•The body uses control systems (loops) to maintain these variables at their respective setpoint after a stimulus causes it to deviate from the setpoint

Homeostatic Regulation (keeping within set limits)

1. Autoregulation (Intrinsic Regulation) - activities of a cell/tissue/organ/system adjust automatically in response to environmental change.

2. Extrinsic Regulation - results from activities of nervous or endocrine systems

-Nervous system: directs rapid, short term, specific responses

-Endocrine system: works through hormones, slow to act but long lasting effects

Homeostatic Control Mechanisms

•There are three interdependent components of a control system:

–Receptor•monitors the variable and responds to changes (stimuli). The receptor sends information regarding the changed variable to the…

–Control center •determines the set point at which the variable is maintained. Then the control center sends information to the…

Homeostasis use requires coordinated efforts of multiple organ systems: human body integrated to support life

–Effector •provides the means to respond to the stimulus (creates an effect) to bring the variable back to the set point

- essentially a muscle or a gland

Homeostatic Control Systems

Homeostatic Control Systems (Loops)

There are 2 different types of control systems

•Most (over 99%) of them are referred to as negative feedback loops where the output of the system (effector) causes a change in the variable which opposes the original stimulus

–If the original stimulus caused a increase in a variable, the effector will cause the variable to decrease back to the set point

–Function like the heating/cooling system in a house to maintain a constant room temperature

Negative Feedback

Negative Feedback

The setpoint for body temperature is 37ºC

•If body temperature increases:–blood vessels dilate increasing blood flow to the skin –sweating occurs

•If body temperature decreases–blood vessels constrict reducing blood to the skin–skeletal muscles contract vigorously (shiver)

Homeostatic Control Systems (Loops)

•The minority (less than 1%) of the systems are referred to as positive feedback systems where the output of the system causes a change in the variable which reinforces the original stimulus

–If the original stimulus caused a increase in a variable, the effector will cause the variable to further increase

Positive Feedback

Anatomical Position

• The anatomical position is a standardized method of observing or imaging the body that allows precise and consistent anatomical references.

• When in the anatomical position, the subject stands.– standing upright– facing the observer, head level– eyes facing forward– feet flat on the floor– arms at the sides– palms turned forward (ventral)

Reclining Position

• If the body is lying face down, it is in the prone position.

• If the body is lying face up, it is in the supine position.

Common Regional Names

cranial (skull), thoracic (chest), brachial (arm), patellar (knee),

cephalic (head), and gluteal (buttock) as

seen in Figure

• Clinical terminology is

based on a Greek or Latin root word.

-Lumbar region = lower back

-Gluteal region = butt

-Pelvic region = hips

-Pubic region = anterior pelvis

-Inguinal region = groin

-Femoral region= thigh

-Crural region= front of leg

-Sural region=calf

-Tarsal region= ankle

-Pedal region= top of foot

-Plantar region= sole of foot

Anatomical Terms - contd.

-Carpal region = wrist

-Manual region = hand

-Abdominal region = belly

Directional Terms

• Directional terms are used to precisely locate one part of the body relative to another and to reduce length of explanations.

• Commonly used directional terms:– dorsal, superior, medial, and distal

• Superior

-towards the head

– The eyes are superior

to the mouth.

• Inferior

– away from the head

– The stomach is inferior

to the heart.

• Dorsal or Posterior– at the back of the body– The brain is posterior to

the forehead.

• Ventral or Anterior– at the front of the body– The sternum is anterior to

the heart.

Dorsal or Ventral

Medial or Lateral• Medial

– nearer to the midline of the body

– The heart lies medial to the lungs.

• Lateral– farther from the midline

of the body

– The thumb is on the lateral side of the hand.

Proximal or Distal• Proximal

– nearer to the attachment of the limb to the trunk

– The knee is proximal to the ankle.

• Distal

– farther from the attachment of the limb to the trunk

– The wrist is distal to the elbow.

Superficial - towards the surface

Deep - towards the interior

Body Cavities

• Body cavities are spaces within the body that help protect, separate, and support internal organs.

Dorsal Body Cavity• The dorsal body cavity is located near the dorsal

surface of the body and has two subdivisions, the cranial cavity and the vertebral canal.

• The cranial cavity is formed by the cranial bones and contains the brain.

• The vertebral (spinal) canal is formed by the bones of the vertebral column and contains the spinal cord.

• Three layers of protective tissue, called meninges, line the dorsal body cavity.

Dorsal Body Cavity

Ventral Body Cavity• Near ventral surface of

body• 2 subdivisions

– thoracic cavity above diaphragm

– abdominopelvic cavity below diaphragm

• Diaphragm = large, dome-shaped muscle

• Organs called viscera• Organs covered with

serous membrane

Serous Membranes

• Thin slippery membrane lines body cavities not open to the outside– parietal layer lines walls of cavities– visceral layer covers viscera within the cavities

• Serous fluid reduces friction

Ventral Body Cavity• The thoracic cavity contains two pleural cavities, and

the mediastinum, which includes the pericardial cavity.– The pleural cavities enclose the lungs.– The pericardial cavity surrounds the heart.

• The abdominopelvic cavity is divided into a superior abdominal and an inferior pelvic cavity.– Viscera of the abdominal cavity include the stomach, spleen,

pancreas, liver, gallbladder, small intestine, and most of the large intestine.

– Viscera of the pelvic cavity include the urinary bladder, portions of the large intestine and internal female and male reproductive structures.

Mediastinum

• The mediastinum is a broad, median partition between the lungs that extends from the sternum to the vertebral column, it contains all contents of the thoracic cavity except the lungs.– heart and great vessels, esophagus, trachea, thymus.

Thoracic Cavity

• Encircled by ribs, sternum, vertebral column and muscle• Divided into 2 pleural cavities by mediastinum • Mediastinum contains all thoracic organs except lungs

Abdominopelvic Cavity

• Inferior portion of ventral body cavity below diaphragm• Encircled by abdominal wall, bones & muscles of pelvis

Abdominopelvic Regions and Quadrants

• To describe the location of organs or abdominopelvic abnormalities easily, the abdominopelvic cavity may be divided into – nine regions by drawing four imaginary lines

as shown in.– quadrants by passing imaginary horizontal and

vertical lines through the umbilicus.

Abdominopelvic Regions & Quadrants

• Describe locations of organs or source of pain• Tic-tac-toe grid or intersecting lines through navel

Clinical Application: Autopsy

• An autopsy is a postmortem examination of the body and dissection of the internal organs to confirm or determine the cause of death.

• An autopsy supplies information relating to the deceased individual.

Planes and Sections• Planes are imaginary flat surfaces that are used to

divide the body or organs into definite areas

• Principal planes include:

– midsagittal (medial) and parasagittal

– frontal (coronal)

– transverse (cross-sectional or horizontal)

– oblique

• Sections

– flat surfaces resulting from cuts through body structures, named according to the plane on which the cut is made (transverse, frontal, and midsagittal sections)

Sagittal Plane

• Sagittal plane– divides the body or an

organ into left and right sides

• Midsagittal plane– produces equal halves

• Parasagittal plane– produces unequal

halves

Other Planes and Sections• Frontal or coronal plane

– divides the body or an organ into front (anterior) and back (posterior) portions

• Transverse(cross-sectional) or horizontal plane– divides the body or an organ into upper

(superior) or lower (inferior) portions

• Oblique plane– some combination of 2 other planes