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The Human Body:An Orientation

Chapter 1

ObjectiveDefine anatomy and physiology, and

describe various specialties of each discipline.

An Introduction to Studying the Human Body

ANATOMY

Describes the structures of the body:

What they are made of

Where they are located

An Introduction to Studying the Human Body

PHYSIOLOGY

Is the study of:

Functions of anatomical structures

Specialties of Anatomy

Gross Anatomy (large anatomy)

Examines large, physical structures

Surface anatomy (exterior features)

Regional anatomy (body areas)

Systemic anatomy (groups of organs working together)

Developmental anatomy (from egg to maturity)

Embryology (before birth)

Specialties of AnatomyMicroscopic Anatomy

Examines cells and molecules

Cytology (cells and their structures)

Histology (tissues and their structures)

SpecialtiesPathological anatomy

diseases

Radiographic anatomy

internal structures using special visualization techniques

Key Concept

Function is dependent on structure

Structure is dependent on function

Levels of OrganizationWhat is the simplest level?

Levels of Organization From simple to complex:

Atoms – the smallest chemical units

Molecules – a group of atoms working together

Organelles – a group of molecules working together

Cells – a group of organelles working together

Tissues – a group of similar cells working together

Organs – a group of different tissues working together

Organ systems – a group of organs working together

Organism – an individual

Self Quiz!!1. The study of the structure of tissue is

called _____.

a) Gross anatomy

b) Cytology

c) Histology

d) Organology

2. Arrange the following list of levels of organization from the smallest level to the largest.

1. Tissue

2. Cell

3. Organ

4. Organelle

5. Organism

6. Organ system

A. 2, 4, 1, 3, 6, 5

B. 4, 2, 1, 3, 6, 5

C. 4, 2, 1, 6, 3, 5

D. 4, 2, 3, 1, 6, 5

E. 2, 1, 4, 3, 5, 6

3. The study of the general form and superficial markings of an organism is called ____ anatomy.

a. Gross

b. Surface

c. Systemic

d. Regional

e. Surgical

ObjectivesExplain the concept of homeostasis and its

significance for organisms.

Describe how negative feedback and positive feedback are involved in homeostatic regulation.

HomeostasisPhysiological systems are constantly

adjusting to maintain a stable environment.

regardless of environmental change

Ex.: You exercise. Your oxygen levels decrease. In response, chemicals are released. The chemical dilates blood vessels. Dilation increases blood flow. Blood flow provides more oxygen.

Homeostatic Regulatory Mechanism

Purpose: keeps system in check

3 parts:

Receptor

Receives a stimulus

Control Center

Processes info, sends out commands

Effector

A cell or organ that responds to the stimulus

Partner ShareUse the example of a thermostat

What is the receptor?

What is the control center?

What is the effector?

Partner ShareUse the example of a thermostat

What is the receptor?

Thermometer (internal or external)

What is the control center?

The thermostat

What is the effector?

The air conditioner which turns on and off to maintain the desired temperature.

Negative FeedbackPrimary mechanism of homeostatic

regulation

The response of the effector negates the stimulus

Ex.: body temperature, blood pressure, blood glucose levels

nervous & endocrine systems

Excess D

blocks a

step

(a) Negative feedback

Negative

feedback

D

D D

D

C

B

A

Enzyme

1

Enzyme

2

Enzyme

3

–

Positive FeedbackThe response of the effector reinforces

the stimulus

Ex.: blood clotting, childbirth

Excess Z

stimulates a

step

(b) Positive feedback

Z

Positive

feedback

Enzyme

4

Enzyme

5

Enzyme

6

Z

Z

Z

Y

X

W

+

What if it fails?No homeostasis = disease or death

Review!!1. The increasingly forceful labor

contractions during childbirth are an example of _____.

a) Receptor activation

b) Effector shutdown

c) Negative feedback

d) Positive feedback

2. Failure of homeostatic regulation in the body results in _____.

a) Autoregulation

b) Extrinsic regulation

c) Disease

d) Positive feedback

What are the anatomical terms used to describe body sections, regions,

and relative positions?

Anatomical PositionBody erect

Palms forward

Thumbs point away

Directional TermsUsed to explain exactly where one body

part is in relation to another

Dorsal vs. ventral

Distal vs. proximal

Medial vs. lateral

Superior vs. inferior

Regional TermsAxial region:

head, neck, trunk

Appendicular region:

upper & lower limbs

Body PlanesFlat surfaces that lie at right angles to

each other

sagittal plane

frontal plane

transverse plane

Sagittal PlaneSeparates body into left and

right halves

midsagittal – in the middle

Frontal PlaneVertical plane

Separates the body into anterior & posterior parts

Transverse PlaneHorizontal

Divides body into superior & inferior parts

Body Cavities & MembranesSpaces that close

to the outside and contain the internal organs

Dorsal Body CavityCNS, 2 subdivisions:

Cranial cavity

within the skull

houses the brain

Spinal cavity

within the vertebral column

houses the spinal cord

Ventral Body CavityAnterior, larger, houses the organs

Thoracic cavity

surrounds the lungs (pleural cavity)

heart (pericardial cavity)

Abdominopelvic cavity

9 regions

4 quadrants

Abdominopelvic Regions

Abdominopelvic Quadrants

Internal Organs