Anatomy & Physiology

Warm Up: List all the organs that you know in the human body (in any

order).

What organs did you come up with?

• Look at the list of organs we have listed on the board…

• In your science notebook, organize them in a way that makes sense to you…

• Share your explanation of organization with the person next to you…

• How do the two compare?

Why are we here?

• Obviously, to learn about human anatomy and physiology.

• But, what does that mean? • Before we begin, we’ve got to figure a few

things out:1. What’s a human?

2. What’s anatomy?

3. What’s physiology?

What are humans?

• Organisms are classified as human because they are:– Animals– Vertebrates

• Possess backbones– Mammals

• Possess:– Mammary glands– Hair– Endothermy (i.e., we generate heat internally)– Heterodonty (i.e., we have teeth w/ different shapes

and functions)– 3 middle ear bones.

What are humans?

– Primates• Possess:

– Opposable thumbs (can you touch your pinky with your thumb?). What advantage does this confer?

– 2 clavicles (collarbones)– Only 2 mammary glands. Why only 2? (Think

about how many kids a woman normally gives birth to.)

– Forward facing eyes with stereoscopic vision (for depth perception)

– Hominids • Bipedal (walk on 2 legs)• Possess a large brain size/body size ratio

• 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 “up or apart”– 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?

Related Fields of Study• An incredibly integral field is pathology –

the study of disease.

• Another super important field is embryology, the study of how a single zygote (i.e., a fertilized egg) turns into a fully-fledged human being with trillions of cells.

Levels of Structure

Chemicals

Cell

Tissue

Organ

Organ System

Organism

Levels of Structure

Chemical Level

Atoms combine to form moleculeswater, sugar, fats, proteins

The function of a molecule is related to its function

Collagen molecules are ropelike protein fibers that give skin structural strength and flexibility

Cells

• 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).

• Organelles themselves are made of these macromolecules and macromolecules are polymers of smaller molecules which consist of atoms of various chemical elements.

A Prototypical Cell

Important Organelles

• Plasma Membrane → Separates the cell exterior from the cell interior (cytoplasm).

Nucleus → Membrane bound structure that contains deoxyribonucleic acid (DNA) which is the set of instructions for the synthesis of all the body’s proteins.

– CAN YOU SEE THE NUCLEUS AND THE PLASMA MEMBRANE IN THE CELL TO THE RIGHT?

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

Organism

• An organism is any living thing considered as a whole.

• The human organism is a complex of organ systems

Can Anatomy & Physiology Be Separated?

• NOOOOOOO!!!!! Absolutely not!• Structure and function are undeniably

connected. We cannot divorce them. • What do we mean by this?

– Can you eat soup with a fork?– Find 2 everyday items and determine

whether/how their structure (anatomy) relates to their function (physiology)

When you consider the structure of an organ, cell, or anything for that matter you must also consider its function!

Anatomic Position

Person standing erect with face directed forward, upper limbs hanging to side and palms of the hands facing forward.

Planes(Midsagittal

plane)↓Parasagittal Plane

Directional Terms

Directional Terms

Supine and Prone

Supine- person lying face upward.Prone- person lying face downward.

Anterior View of Body Parts and Regions

Posterior View of Body Parts and Regions

Body Cavities

Abdominal Quadrants

9 Subdivisions of

Abdominal Region

Stayin’ Alive

• Your body has about 100 trillion cells in it.• 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

The Cell’s Environment

• In order to keep the right amount of stuff in the cell, we’ve got to make sure that all the fluid surrounding our cells (i.e., the extracellular fluid) has the right assortment of nutrients, ions, etc.

• We keep both our cells and the fluid surrounding our cells in a dynamically stable environment via a process called HOMEOSTASIS.

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

Blood Pressure

• BP is a variable that we’ve got to maintain at a certain level

• We have sensory receptors that measure the BP in the body. They’re located in the aorta (the big blood vessel coming out of the heart) and in the carotid arteries (the large vessels that bring blood to the brain).

• These pressure receptors measure BP and then send the info (we can call this input) to a control center in the brain – the particular BP control center is in the medulla oblongata of the brain

Blood Pressure

• We call the connection btwn the receptor and the control center the afferent pathway.

• In the control center, the input BP is compared with a set value.

• If there is a difference between the current BP value and the reference BP value then we’ve got an error.

• And we’ve got to fix that error!

Blood Pressure

• The control center will signal effector organs – such as the heart in this case – to alter their activity. This process is called output.

• The connection between the control center and the effector organ is called the efferent pathway.

Blood Pressure

• Suppose the current BP is too high.• The effector must act in a way to decrease it – so

the medulla oblongata (the control center) would signal the heart to decrease the force and rate of its contractions; this would decrease BP.

• Notice that the original stimulus was an INcrease in BP and the body’s response was to act so as to DEcrease BP.

• The stimulus is opposite the response!

Negative Feedback

• B/c 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

• Let’s look at BP again:

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

Some Important Themes

1. Biology is hierarchical with each level building on the level below it.

2. Each level of biological structure has emergent properties.

3. Cells are an organism’s basic unit of structure and function.

4. Structure and function are correlated at all levels of biological organization!!!!!!!!

5. Regulatory mechanisms ensure a dynamic balance in living systems.

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!

Homeostasis is Important!

• Most of the physiological processes that occur in your body are designed to maintain homeostasis. – ALWAYS KEEP THIS IN MIND!

• Question: Does the magnitude (i.e., size) of the error signal influence the magnitude of the response?

• Just to recap, let’s look at a couple more figures!

Homeostasis is

DYNAMIC!

What this means is that the homeostatic variables are NOT kept rigidly fixed upon a single value. They are kept within a certain range, and when they exit that range – that’s when negative feedback loops turn on to bring them back.

Is your body temperature always exactly 98.6F?

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

Dangerous Positive Feedback

Rise in body temperature

Increase in body metabolism

Increase in body heat production

What stops a positive feedback loop?

Characteristics of Life

1. Organization

2. Metabolism

3. Responsiveness

4. Growth

5. Development

6. Reproduction

Organization

• Parts of the organism have specific relationships to each other and the parts interact to perform specific functions.

• Example:• Cells → Organelles → Large molecules

Metabolism

• all the chemical reactions taking place in an organism

• Example- Break down food molecules → source of energy and raw materials → build own molecules

Responsiveness

• Ability of an organism to sense changes in its internal or external environment and adjust to those changes.

• Examples: – moving toward food or water or away from

danger– Adjustments to maintain internal environment

(body temperature increases → sweat)

Growth

• Cells increase in size or number..produces an overall enlargement of all or part of and organism

• Example: – muscles enlarged by exercise has larger

muscles cells. – Skin of adult has more cells than skin of a baby

Development

• Changes an organism undergoes through time…fertilization to death.

• Growth, Differentiation and Morphogenesis• Example-

– following fertilization, generalized cells specialize to become specific cell types ( skin, bone, muscle)

– differentiated cells form tissues and organs

Serous Membranes

Serous Membranes