Chapter 1 - Intro to the Human Body

Human Anatomy

the study of body structure and the relationships between them

Human Physiology

the science of body functions - how body parts work

Levels of Organization

• chemical

• cells

• tissues

• organs

• systems

• organism

Levels of Organization: Chemical

• atoms: common atoms found in the human body (oxygen, hydrogen, nitrogen, carbon)

• molecules: two or more atoms joined together

Inorganic molecules don’t have

don’t have C-H bonds

Organic molecules do have

do have C-H bonds

Levels of Organization: Cells

• composed of combinations of molecules

• basic structural and functional units of an organism

Basic Cell Types Examples

• muscle fibres

• neurons

• osteocytes

• epithelial cells

• cardiac muscle

Approximately ___ different kinds of cells

210

Levels of Organization: Tissues

• group of cells and the materials surrounding them that work together to perform similar function

• epithelium, connective, muscular, nervous

Levels of Organization: Organs

• structures composed of two or more different types of tissues that have specific functions

• most organs have all four types of tissues

Levels of Organization: Systems

• consists of related organs with common functions

• 11 total in the human body

Levels of Organization: Organism

• consists of a collection of organs

• all parts of the body must be functioning together in a process called homeostasis

Skeletal System parts and functions

• consists of bones, joints, and associated cartilages

• provides support, movement, and protection for internal organs

• stores minerals and produces red blood cells, white blood cells, and platelets

Muscular System parts and functions

• consists of named muscles, smooth, and cardiac muscle

• facilitate movement and maintain posture

• generate heat

Cardiovascular System parts and functions

• consists of heart, blood, and blood vessels

• vessels carry blood containing gases and nutrients to specific locations

• regulates body temp, acid-base, and water balance

• blood components defend against disease have repair functions

Nervous System parts and functions

• consists of the brain, spinal cord, nerves, and sensory organs

• generates action potentials to regulate body activity

• interprets and responds to detected changes

Essential Life Processes

• metabolism

• responsiveness

• movement

• growth

• differentiation

• reproduction

Essential Life Processes: Metabolism

• the sum of all catabolic and anabolic chemical processes that occur in the body

Catabolic

breaking down

Anabolic

building up

Essential Life Processes: Responsiveness

• body’s ability to detect and respond to changes which might represent an opportunity or threat

Essential Life Processes: Movement

• any motion including movement of tiny subcellular structures, or movement inside cells or organs

Essential Life Processes: Growth

• involves an increase in body size due to an increase in existing cells, number of cells, or both

Essential Life Processes: Differentiation

• development of a cell from an unspecialized to specialized state

Stem Cells

give rise to cells that undergo differentiation

Essential Life Processes: Reproduction

• formation of new cells (growth, repair, or replacement) or the production of a new individual

Homeostasis

• a condition of equilibrium in the body’s internal environment

• dynamic condition meant to keep body functions in the narrow range compatible with maintaining life

• controlled by nerve impulses and hormones

Body Fluids and three main fluids

dilutes watery solutions containing dissolved chemical inside or outside the cell

• intracellular fluid

• extracellular fluid

• interstitial fluid

Intracellular Fluid (ICF)

fluid within cells

Extracellular Fluid (ECF)

fluid outside the cells

Interstitial Fluid

ECF between cells and tissues

Important Body Fluids

• blood plasma

• lymph

• cerebrospinal fluid (CSF)

• synovial fluid

• aqueous humor

Blood Plasma

ECF within blood vessels

Lymph

ECF within lymphatic vessels

Cerebrospinal Fluid (CSF)

ECF surrounding the brain and spinal cord

Synovial Fluid

ECF in joints

Aqueous Humor

ECF in eyes

Cellular Function depends on:

composition of the interstitial fluid as it changes as substance as it moves between plasma and interstitial fluid

Movement back and fourth across capillary walls does:

• provide nutrients (glucose, oxygen, ions) to tissue cells

• removes waste (carbon dioxide, metabolic byproducts)

Control of Homeostasis is challenged by:

• physical insults

• changes in internal environment

• physiological stressors

Physical Insults

intense heat or lack of oxygen

Feedback Systems - Cycle of Events

• body is monitored and remonitored by checkpoints

• each monitored variable is termed a controlled condition

Three Basic Components

• receptor

• control center

• effector

Receptor

body structure that monitors changes in a controlled condition and sends input to the control center

Control Center

sets a range of values to be maintained - usually done by the brain, evaluates input received from receptors and generates output command

Effector

receives output command from control center and produces a response or effect that changes the controlled condition to return back to optimal levels

Negative Feedback Systems

• reverses a change in a controlled condition

• blood pressure as an example

Positive Feedback Systems

• reinforces a change in one of the body’s controlled conditions

• childbirth as an example