Chapter 4Organ Systems of the Body

Definitions and Concepts

• Organ—a structure made up of two or more kinds of tissues organized in such a way that they can together perform a more complex function than can any tissue alone

• Organ system—a group of organs arranged in such a way that they can together perform a more complex function than can any organ alone

• A knowledge of individual organs and how they are organized into groups makes more meaningful the understanding of how a particular organ system functions as a whole

Organ Systems• Integumentary system

– Structure—organs• Skin• Hair• Nails• Sense receptors• Sweat glands• Oil glands

Organ Systems

• Integumentary system– Functions

• Protection• Regulation of body temperature• Synthesis of chemicals• Sense organ

Organ Systems

• Skeletal system (Figure 4-3)– Structure

• Bones• Joints

Organ Systems

• Skeletal system– Functions

• Support• Movement (with joints and muscles)• Storage of minerals• Blood cell formation

Organ Systems• Muscular system

– Structure• Muscles

– Voluntary or striated– Involuntary or smooth– Cardiac

Organ Systems• Muscular system

– Functions• Movement• Maintenance of body posture• Production of heat

Organ Systems• Nervous system

– Structure• Brain• Spinal cord• Nerves• Sense organs

Organ Systems• Nervous system

– Functions• Communication• Integration• Control• Recognition of sensory stimuli• System functions by production of nerve

impulses caused by stimuli of various types• Control is fast-acting and of short duration

Organ Systems• Endocrine system

– Structure• Pituitary gland• Pineal gland• Hypothalamus• Thyroid gland• Parathyroid glands

• Thymus gland• Adrenal glands• Pancreas• Ovaries (female)• Testes (male)

Organ Systems• Endocrine system

– Functions• Secretion of special substances called

hormones directly into the blood• Same as nervous system—communication,

integration, control• Control is slow and of long duration

Organ Systems• Endocrine system

– Functions• Examples of hormone regulation

– Growth– Metabolism– Reproduction– Fluid and electrolyte balance

Organ Systems• Cardiovascular (circulatory) system

– Structure• Heart• Blood vessels

Organ Systems• Cardiovascular (circulatory) system

– Functions• Transportation• Regulation of body temperature• Immunity (body defense)

Organ Systems• Lymphatic and immune systems

– Lymphatic system• Structure

– Lymph nodes– Lymphatic vessels– Thymus– Spleen

Organ Systems• Lymphatic and immune systems

– Lymphatic system• Functions

– Transportation– Immunity

Organ Systems• Lymphatic and immune systems

– Immune system• Structure

– Unique cells» Phagocytes» Secretory cells

– Specialized protein compounds» Antibodies» Complements

Organ Systems• Lymphatic and immune systems

– Immune system• Functions

– Phagocytosis of bacteria – Chemical reactions to provide protection

Organ Systems• Respiratory system

– Structure• Nose• Pharynx• Larynx• Trachea• Bronchi• Lungs

Organ Systems• Respiratory system

– Functions• Exchange of waste gas (carbon dioxide) for

oxygen in the lungs• Area of gas exchange in the lungs called alveoli• Filtration of irritants from inspired air• Regulation of acid-base balance

Organ Systems• Digestive system

– Structure• Primary organs

– Mouth– Pharynx– Esophagus– Stomach

– Small intestine– Large intestine– Rectum– Anal canal

Organ Systems• Digestive system

– Structure• Accessory organs

– Teeth– Salivary glands– Tongue– Liver– Gallbladder– Pancreas– Appendix

Organ Systems• Digestive system

– Functions• Mechanical and chemical breakdown

(digestion) of food• Absorption of nutrients• Undigested waste product that is eliminated is

called feces• Appendix is a structural but not a functional

part of digestive system• Inflammation of appendix is called appendicitis

Organ Systems• Urinary system

– Structure– Kidneys– Ureters– Urinary bladder– Urethra

Organ Systems• Urinary system

– Functions• “Clearing” or cleaning blood of waste

products—waste product excreted from body

is called urine• Electrolyte balance• Water balance• Acid-base balance• In male, urethra has urinary and reproductive

functions

Organ Systems• Reproductive system

– Structure• Male

– Gonads—testes– Genital ducts—vas deferens, urethra– Accessory organ—prostate– Supporting structures—genitalia (penis and

scrotum)

Organ Systems• Reproductive system

– Structure• Female

– Gonads—ovaries– Accessory organs—uterus, uterine

(fallopian) tubes, vagina– Supporting structures—genitalia (vulva),

mammary glands (breasts)

Organ Systems• Reproductive system

– Functions• Survival of species• Production of sex cells (male: sperm; female:

ova)• Transfer and fertilization of sex cells• Development and birth of offspring• Nourishment of offspring• Production of sex hormones

Integration of Body Organ System Functions

• No one body system functions entirely independently of other systems

• All body systems are structurally and functionally interrelated and

interdependent

Organ Replacement• Loss of function in nonvital organs is not

immediately life threatening; loss of function

in vital organs is immediately life threatening• Loss of function in organs can be treated by

organ replacement– Artificial organs (prostheses) – Organ transplantation– Free-flap surgery– Stem cell treatment