• What is anatomy?– Anatomy is defined as the study of…

• Structure refers to the shapes, sizes, and characteristics of the components of the human body.

• The word anatomy comes from 2 words:– Ana which means “throughout”– Tomos which means “to cut”

Why these two words????

Types of Anatomy

• We can divide our study of structure into 2 parts:• Study of stuff seen by the naked eye (Gross Anatomy).

• Study of stuff seen ONLY with the microscope (Microanatomy).– We can divide microanatomy into:

» Histology – study of tissues

» Cytology – study of individual cells.

Physiology

• Physiology is defined as the study of function – so human physiology attempts to explain how and why humans function.

• Physiology is where we figure out how stuff works.

• How do muscles contract?

• How do we run?

• How does our heart beat?

Levels of Structure

• In order to understand how something is built and how something works, you must look at all of its components and analyze them both individually and together.

• An organism (such as a human being) may be broken down as illustrated on the left.

Cell

Tissue

Organ

Organ System

Organism

Levels of Structure

• The basic unit of life is the cell.

• All living organisms are composed of one or more cells.

• The human body contains about 100 trillion cells.

• There are about 200 different types of cells in the human body.

• The different types of cells have different features but for the most part, all cells are made up of organelles and various macromolecules (e.g., proteins, lipids, carbohydrates and nucleic acids).

More Levels of Structure

• Similar cells and cell products come together to form tissues.

• A structure made of 2 or more tissue types that perform a particular function is an organ.

• A group of organs with a unique collective function is an organ system. There are 11 of these in the human body.

Integumentary System

• Structures: - Skin, hair, sweat and oil glands

• Functions: - Forms the external body covering

- Protects deeper tissues from injury

- Involved in vitamin D synthesis

- Prevents desiccation, heat loss, and pathogen entry

- Site of pain and pressure receptors

Skeletal System

• Structures:– The 206 bones of the human body

• Functions:– Protects and supports body organs

• What characteristics might bone have that allows it to support and protect?

– Provides a framework that muscles can use to create movement

– Hemopoiesis (synthesis of blood cells)– Mineral storage

• Bone contains 99% of the body’s store of what mineral? (Hint you can get this mineral from drinking milk)

Muscular System

• Structures:– The 600+ muscles of

the body

• Functions:– Locomotion– Manipulation of the

environment– Maintaining posture– Thermogenesis

(generation of heat)

Nervous System

• Structures: – Brain, spinal cord, and

peripheral nerves

• Functions:– Fast-acting control system

of the body– Monitoring of the internal

and external environment and responding (when necessary) by initiating muscular or glandular activity

Endocrine System

• Structures:– Hormone-secreting glands

• Pituitary, Thyroid, Thymus, Pineal, Parathyroid, Adrenal, Pancreas, Small Intestine, Stomach, Testes, Ovaries, Kidneys, Heart

• Functions:– Long-term control system of the

body– Regulates growth, reproduction,

and nutrient use among other things.

Cardiovascular System

• Structures: – Heart, Blood vessels (arteries, veins,

and capillaries)

• Functions:– The heart pumps blood thru the

blood vessels.– Blood provides the transport

medium for nutrients (glucose, amino acids, lipids), gases (O2, CO2), wastes (urea, creatinine), signaling molecules (hormones), and heat.

Lymphatic/Immune System

• Structures:– Lymphatic vessels, Lymph nodes,

Spleen, Thymus, Red bone marrow

• Functions:– Returning “leaked” fluid back to

the bloodstream, – Disposal of debris– Attacking and resisting foreign

invaders (pathogens i.e., disease-causing organisms)

Respiratory System

• Structures:– Nasal cavity, pharynx,

trachea, bronchi, lungs

• Functions:– Constantly supply the

blood with O2, and remove CO2

– Regulate blood pH

Digestive System

• Structures:– Oral cavity, esophagus, stomach,

small intestine, large intestine, rectum, salivary glands, pancreas, liver, gallbladder

• Functions:– Ingestion and subsequent breakdown

of food into absorbable units that will enter the blood for distribution to the body’s cells

Urinary System

• Structures:– Kidneys, ureters,

urinary bladder,

urethra

• Functions:– Removal of nitrogenous

wastes– Regulation of body’s

levels of water, electrolytes, and acidity

Reproductive System

• Structures:– Male:

• Testes, scrotum, epididymis, vas deferens, urethra, prostate gland, seminal vesicles, penis

– Female:• Ovary, uterine tube, uterus,

cervix, vagina, mammary glands

• Functions:– Production of offspring

Survival Needs: Stayin’ Alive!

• For your life to NOT end abruptly, these cells need to have the correct amount of:

• Oxygen

• Nutrients

• Waste removal

• Heat

• Ions (sodium, calcium, etc.)

• Lots of other stuff

Necessary Life Functions

• Maintain Boundaries

• Movement

• Responsiveness

• Digestion

• Metabolism

• Excretion

• Growth

• Reproduction

Homeostasis

• Defined as the body’s ability to maintain stable internal conditions in spite of the changing external conditions.

• We just said that our body needs to have the right amount of stuff (i.e., temperature, blood [glucose], pH etc.) at all times in order to function properly.

• First, let’s refer to all this stuff as “different variables”

Note: the brackets surrounding the word glucose in the above paragraph mean “concentration of glucose,” i.e., how much glucose is dissolved in a particular fluid (blood in this case)

Let’s use a thermostat as an example

• In order to keep the temperature in my house at the right level, the thermostat must first measure the current temperature in the house.

• After the thermostat measures the temperature, it compares the current value to a preset standard value. – If there is no difference then there’s nothing to do.– However, if it’s too hot or too cold, the thermostat has

to send a signal to the furnace or air conditioner to change the temperature of the house so that it equals the standard value.

Let’s clarify some stuff.

• In the previous example we had a:1. Variable temperature2. Measuring implement thermostat3. Control center also the thermostat4. A preset or standard value for the variable5. Effectors the air conditioner and furnace

• Similar situations arise in the human body where there are lots of variables that we want to maintain at certain precise levels

Negative Feedback

• The movement of a variable in one direction causes the body to enact processes that cause the variable to move in the opposite direction (so as to return the value to the correct level) – we call it negative feedback

Increased BP

Sensed by pressure receptors in aortic arch and carotid sinus

Input sent via afferent pathway to medulla oblongata

Current BP compared with set point and error signal generated

Output sent along efferent pathway to heart and blood vessels

Heart rate & force of contraction decrease

Blood vessel diameter increases

BP DECREASES

Why is Negative Feedback so common in the body?

• Think about it! Every time a variable starts changing too much, we’ve got to bring it back to normal. We’ve got to counteract its change.

• THAT’S NEGATIVE FEEDBACK

• Other examples you will encounter:– Maintenance of blood [Ca2+], blood [Glucose],

blood pH, and many others

When does a negative feedback process end?

THINK ABOUT IT!

• A negative feedback process begins when a particular variable leaves its homeostatic range.

• The process ends when that variable is back within its normal range.

• Negative feedback processes (or loops) are self-terminating.

MAKE SURE YOU UNDERSTAND WHY!

What about Positive Feedback?

• Positive feedback occurs when the response amplifies or magnifies the stimulus that produced it.

• In other words, a variable is altered and then the body’s response alters that variable even more in the same direction.

• How does this differ from negative feedback?• Which do you suppose is more common in the

body: positive or negative feedback?

Positive Feedbackin Childbirth

Positive Feedbackin Blood Clotting

What stops a positive feedback loop?

The Language of AnatomyThe Language of Anatomy

Slide 1.21Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Special terminology is used to prevent misunderstanding

• Exact terms are used for:

• Position

• Direction

• Regions

• Structures

Orientation and Directional TermsOrientation and Directional Terms

Slide 1.22Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Table 1.1

Orientation and Directional TermsOrientation and Directional Terms

Slide 1.23Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Table 1.1 (cont)

Body LandmarksBody Landmarks

Slide 1.24Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Anterior

Figure 1.5a

Body LandmarksBody Landmarks

Slide 1.25Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Posterior

Figure 1.5b

Body PlanesBody Planes

Slide 1.26Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 1.6

Body CavitiesBody Cavities

Slide 1.27Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 1.7

Abdominopelvic QuadrantsAbdominopelvic Quadrants

Slide 1.28Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 1.8a

Abdominopelvic RegionsAbdominopelvic Regions

Slide 1.29Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 1.8b

Abdominopelvic Major OrgansAbdominopelvic Major Organs

Slide 1.30Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 1.8c