The Human Body: An Orientation Chapter 1 The Human Body: An Orientation

The Human Body—An Orientation Anatomy Study of the structure and shape of the body and its parts Physiology Study of how the body and its parts work or function

Anatomy—Levels of Study Gross anatomy Large structures Easily observable Figure 14.1

Anatomy—Levels of Study Microscopic Anatomy Very small structures Can only be viewed with a microscope Figure 14.4c–d

Sub-divisions of Human Physiology Cellular Physiology- interactions b/w cell parts and organelle function. Developmental Physiology- changes throughout the development of an organism. Pathological Physiology- function changes that occur to organs over time.

Characteristics of Living things Metabolism Responsiveness Growth Movement Differentiation Reproduction

Levels of Structural Organization Smooth muscle cell Molecules Atoms Smooth muscle tissue Epithelial tissue Connective tissue Blood vessel (organ) Cardio- vascular system Cellular level Cells are made up of molecules Tissue level Tissues consist of similar types of cells Organ level Organs are made up of different types of tissues Organ system level Organ systems consist of different organs that work together closely Organismal level Human organisms are made up of many organ systems Chemical level Atoms combine to form molecules Levels of Structural Organization Figure 1.1

How are cells bound together? Similar cells are bound by the matrix! This could be liquid, solid or semi-solid in nature. Ex: Blood-liquid, bone cells-solid Similar cells bound together by the matrix are considered TISSUES. The study of tissues is called Histology.

4 Principal tissues & functions! 1- Epithelial- covers body and organ surfaces, lines body cavities. Involved in protection, absorption, excretion, and secretion. 2- Connective- binds, supports and protects body parts. 3- Muscle- Permits locomotion by moving the skeleton. 4- Nervous- initiates and transfers electrical impulses that coordinate the body 4 Principal tissues & functions!

Necessary Life Functions Maintain boundaries Movement Locomotion Movement of substances Responsiveness Ability to sense changes and react Digestion Break-down and absorption of nutrients

Necessary Life Functions Metabolism—chemical reactions within the body Produces energy Makes body structures Excretion Eliminates waste from metabolic reactions

Necessary Life Functions Reproduction Produces future generation Growth Increases cell size and number of cells

Survival Needs Nutrients Oxygen Chemicals for energy and cell building Includes carbohydrates, proteins, lipids, vitamins, and minerals Oxygen Required for chemical reactions

Survival Needs Water Stable body temperature Atmospheric pressure 60–80% of body weight Provides for metabolic reaction Stable body temperature Atmospheric pressure Must be appropriate

Interrelationships Among Body Systems Figure 1.3

Homeostasis Homeostasis—maintenance of a stable internal environment A dynamic state of equilibrium Homeostasis is necessary for normal body functioning and to sustain life Homeostatic imbalance A disturbance in homeostasis resulting in disease

Variable (in homeostasis) Input: Information sent along afferent pathway to Control center Output: Information sent along efferent pathway to activate Receptor (sensor) Effector Change detected by receptor Response of effector feeds back to influence magnitude of stimulus and returns variable to homeostasis Stimulus: Produces change in variable Imbalance Variable (in homeostasis) Imbalance Figure 1.4

Variable (in homeostasis) Figure 1.4, step 1a

Variable (in homeostasis) Stimulus: Produces change in variable Imbalance Variable (in homeostasis) Imbalance Figure 1.4, step 1b

Variable (in homeostasis) Receptor (sensor) Change detected by receptor Stimulus: Produces change in variable Imbalance Variable (in homeostasis) Imbalance Figure 1.4, step 2

Variable (in homeostasis) Input: Information sent along afferent pathway to Control center Receptor (sensor) Change detected by receptor Stimulus: Produces change in variable Imbalance Variable (in homeostasis) Imbalance Figure 1.4, step 3

Variable (in homeostasis) Input: Information sent along afferent pathway to Control center Output: Information sent along efferent pathway to activate Receptor (sensor) Effector Change detected by receptor Stimulus: Produces change in variable Imbalance Variable (in homeostasis) Imbalance Figure 1.4, step 4

Variable (in homeostasis) Input: Information sent along afferent pathway to Control center Output: Information sent along efferent pathway to activate Receptor (sensor) Effector Change detected by receptor Response of effector feeds back to influence magnitude of stimulus and returns variable to homeostasis Stimulus: Produces change in variable Imbalance Variable (in homeostasis) Imbalance Figure 1.4, step 5

Maintaining Homeostasis The body communicates through neural and hormonal control systems Receptor Responds to changes in the environment (stimuli) Sends information to control center

Maintaining Homeostasis Control center Determines set point Analyzes information Determines appropriate response Effector Provides a means for response to the stimulus

Feedback Mechanisms Negative feedback Includes most homeostatic control mechanisms Shuts off the original stimulus, or reduces its intensity Works like a household thermostat

Feedback Mechanisms Positive feedback Increases the original stimulus to push the variable farther In the body this only occurs in blood clotting and during the birth of a baby

The Language of Anatomy Special terminology is used to prevent misunderstanding Exact terms are used for Position Direction Regions Structures

Regional Terms Anterior body landmarks Figure 1.5a

Regional Terms Posterior body landmarks Figure 1.5b

Directional Terms Table 1.1 (1 of 3)

Directional Terms Table 1.1 (2 of 3)

Directional Terms Website Fill in the blanks! Fill in the blanks 2 Table 1.1 (3 of 3)

Body Planes and Sections A sagittal section divides the body (or organ) into left and right parts A median, or midsagittal, section divides the body (or organ) into equal left and right parts A frontal section divides the body (or organ) into anterior and posterior parts A transverse, or cross, section divides the body (or organ) into superior and inferior parts

Body Planes and Sections interactive!! Interactive 2 Figure 1.6

These are computed tomography scans and magnetic resonance images. CT Scans & MRI’s These are computed tomography scans and magnetic resonance images. These scans are much more helpful because they can give both sagittal and transverse images as compared to X-rays which can only be taken on a vertical plane.

Body Cavities Dorsal body cavity Ventral body cavity Cranial cavity houses the brain Spinal cavity houses the spinal cord Ventral body cavity Thoracic cavity houses heart, lungs and others Abdominopelvic cavity houses digestive system and most urinary system organs

Body Cavities Figure 1.7

Abdominopelvic Quadrants Figure 1.8a

Abdominopelvic Regions Web! Figure 1.8b

Abdominopelvic Major Organs Game Website Figure 1.8c