Introduction to Anatomy

Definitions Anatomy – Study of body structures and their relationships to each other. Anatomy – Study of body structures and their relationships to each other. Always involves question “What is it?” Always involves question “What is it?”

Physiology – Study of how the body structures work together to maintain life. Physiology – Study of how the body structures work together to maintain life. Involves the question “How does it work?” Involves the question “How does it work?”

Levels of Organization Atoms  Molecules  Cells  Tissues  Organs  Organ Systems  Organisms H + C + O  C 6 H 12 O 6  Muscle Cells  Muscle Tissues  Heart  Circulatory System  Human

Chemical level Atoms combine to form molecules Cellular level Cells are made up of molecules Tissue level Tissues consist of similar types of cells 5 Organ system level Organ systems consist of different organs that work together closely Organ level Organs are made up of different types of tissues 6 Organismal level The human organism is made up of many organ systems Atoms Molecules Smooth muscle cell Smooth muscle tissue Connective tissue Smooth muscle tissue Epithelial tissue Blood vessel (organ) Heart Blood vessels Cardiovascular system Levels of Structural Organization Figure 1.1

Organ Systems 12 Different Organ Systems 12 Different Organ Systems Each specializes in carrying out a specific function Each specializes in carrying out a specific function Example – Muscular system specializes in moving Skeletal system specializes in support

Structure and Function There is an intimate relationship between structure and function. One determines the other. There is an intimate relationship between structure and function. One determines the other.

Explain how the structure of each of the following determines the function for which it can be used. a. fork a. fork b. hand b. hand c. incisors c. incisors

Functions of Life Separate internal and external environments Separate internal and external environments Move Move Respond to stimuli & communicate Respond to stimuli & communicate Digest food Digest food Carry out chemical reactions in cells (metabolism) Carry out chemical reactions in cells (metabolism) Excrete wastes Excrete wastes Reproduce Reproduce Grow Grow

All functions help to maintain homeostasis Homeo = “same” Homeo = “same” Stasis = “same” Stasis = “same” Homeostasis – keep a stable internal environment even though things inside and outside the body are changing Homeostasis – keep a stable internal environment even though things inside and outside the body are changing

Communication is Essential for Homeostasis 2 systems control communication: 2 systems control communication: –Nervous –Endocrine

Stimulus The change in the environment The change in the environment It needs to be reported to the body It needs to be reported to the body Examples – change in temperature, change in glucose levels, change in water levels Examples – change in temperature, change in glucose levels, change in water levels

3 parts of homeostatic control mechanisms: Receptor – receives information from the environment as a stimulus Receptor – receives information from the environment as a stimulus Control center – analyzes info; decides if anything needs to be done Control center – analyzes info; decides if anything needs to be done Effector – responds to the control center to make a change if necessary Effector – responds to the control center to make a change if necessary

Example Receptor – Sun (the stimulus) warms your body. Temperature receptors in skin send info to brain. Receptor – Sun (the stimulus) warms your body. Temperature receptors in skin send info to brain. Control center – Brain sees that body is getting too warm. Sends signal to effectors to cool the body. Control center – Brain sees that body is getting too warm. Sends signal to effectors to cool the body. Effectors – Sweat glands. Release sweat to cool body. Effectors – Sweat glands. Release sweat to cool body.

Feedback The effector causes a change. The effector causes a change. Results of the change then FEEDBACK to the control center. Results of the change then FEEDBACK to the control center.

2 Types of Feedback 1. Negative – Most common type in body. Output from the effector shuts off the stimulus. Helps keep things stable. Works just like the air conditioning system.

Negative system--stimulus causes a response which reduces the stimulus.

THE HOMEOSTATIC CONTROL OF BLOOD GLUCOSE LEVELS is a negative feedback system

2. Positive feedback– rare in body. The output of the effector causes more of the change. Not useful in homeostasis. Helps bring about rapid changes. Examples – in labor - in blood clotting

Positive feedback: stimulus causes a response which increases the stimulus. This system pushes the conditions to an extreme.

Homeostatic Imbalance Causes disease Causes disease The body cannot tolerate drastic changes The body cannot tolerate drastic changes Occurs naturally as we age – homestatic systems do not work as well Occurs naturally as we age – homestatic systems do not work as well Systems can be damaged or injured Systems can be damaged or injured

Language of Anatomy Position and Directional Terms Position and Directional Terms Regional Terms Regional Terms Body Planes and Sections Body Planes and Sections Body Cavities and Membranes Body Cavities and Membranes

Position Terms Anatomical position – helps describe body parts. Anatomical position – helps describe body parts. Resembles standing at attention except palms face forward and thumbs point away from body

Directional Terms Explains where one body structure is in relation to another. Explains where one body structure is in relation to another. –Proximal – closer to the midline –Distal – farther from the midline –Superior – closer to the head –Inferior – closer to the feet –Anterior – closer to the front –Posterior – closer to the rear

Regional Terms Two main regions: Two main regions: –Axial : head, neck, and truck –Appendicular : limbs (arms and legs)

Body Planes To study anatomy, body can be cut along a plane (flat surface). To study anatomy, body can be cut along a plane (flat surface). Sagittal (“arrow”) plane divides body vertically into left and right sections. Sagittal (“arrow”) plane divides body vertically into left and right sections. If sagittal plane is on midline = midsaggital If sagittal plane is on midline = midsaggital

More planes... Frontal plane – divides body vertically into anterior (front) and posterior (back). Frontal plane – divides body vertically into anterior (front) and posterior (back). Transverse plane – a horizontal plane that divides the body into superior (top) and inferior (bottom) Transverse plane – a horizontal plane that divides the body into superior (top) and inferior (bottom)

Transverse plane through mid section

Body Cavities Axial portion of body contains 2 large cavities: 1. Dorsal body cavity – contains brain and spinal cord

2. Ventral body cavity is divided into 2 subdivisions: a. thoracic cavity : chest, contains heart and lungs b. abdominopelvic cavity : 2 parts i. Abdomen – most organs ii. Pelvis – bladder & reproductive structures

Membranes in Cavities Ventral body cavity lined with serous membrane – thin, double layered Ventral body cavity lined with serous membrane – thin, double layered Same membrane covers organs Same membrane covers organs Layers of membrane separated by serous fluid – reduces friction Layers of membrane separated by serous fluid – reduces friction

1-36 Medical Imaging Allows visualization of structures without surgery Allows visualization of structures without surgery Useful for confirmation of diagnosis Useful for confirmation of diagnosis Examples of imaging techniques Examples of imaging techniques

1-37 Conventional Radiography A single burst of xrays A single burst of xrays Produces 2-D image on film Produces 2-D image on film Known as radiography or xray Known as radiography or xray Poor resolution of soft tissues Poor resolution of soft tissues Major use is osteology Major use is osteology

1-38 Computed Tomography (CT Scan) Moving x-ray beam Moving x-ray beam Image produced on a video monitor of a cross-section through body Image produced on a video monitor of a cross-section through body Computer generated image reveals more soft tissue detail Computer generated image reveals more soft tissue detail –kidney & gallstones Multiple scans used to build 3D views Multiple scans used to build 3D views

1-39 Ultrasound (US) High-frequency sound waves emitted by hand- held device High-frequency sound waves emitted by hand- held device Safe, noninvasive & painless Safe, noninvasive & painless Image or sonogram is displayed on video monitor Image or sonogram is displayed on video monitor Used for fetal ultrasound and examination of pelvic & abdominal organs, heart and blood flow through blood vessels Used for fetal ultrasound and examination of pelvic & abdominal organs, heart and blood flow through blood vessels

1-40 Magnetic Resonance Imaging (MRI) Body exposed to high- energy magnetic field Body exposed to high- energy magnetic field Protons align themselves relative to magnetic field Protons align themselves relative to magnetic field Pulse of radiowaves used to generate an image on video monitor Pulse of radiowaves used to generate an image on video monitor Can not use on patient with metal in their body Can not use on patient with metal in their body Reveals fine detail within soft tissues Reveals fine detail within soft tissues

1-41 Positron Emission Tomography(PET) Substance that emits positively charged particles is injected into body Substance that emits positively charged particles is injected into body Collision with negatively charged electrons in tissues releases gamma rays Collision with negatively charged electrons in tissues releases gamma rays Camera detects gamma rays & computer generates image displayed on monitor Camera detects gamma rays & computer generates image displayed on monitor