Why are we here Obviously to learn about

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. 2. 3. What’s a human? What’s anatomy? 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?

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.

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. • In doing these collective and separate analyses, you must examine things at multiple structural levels, i. e. , one must break them down from large to small – this is called reductionism • An organism (such as a human being) may be broken down as illustrated on the left. Organelle Cell Tissue 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 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? • Mitochondria → Structure bound by a double membrane and the site at which the energy stored in sugars and other organic molecules is transferred to ATP, the chemical which acts as the “currency” for energy in the cell. • Ribosomes → Not bound by a membrane. Sites of protein synthesis. May be free – floating in the cytoplasm – or bound to the endoplasmic reticulum. Are the 2 pictures on this page to the same scale? How do you know?

Important Organelles • Rough Endoplasmic Reticulum → Membranous set of tubes with ribosomes studded along its surface. Site of the synthesis of proteins that are destined to be exported from the cell. • Smooth Endoplasmic Reticulum → ER w/o the attached ribosomes. Site of cellular lipid synthesis, among other things. • Golgi Apparatus → Membrane bound organelle responsible for determining the direction of proteins synthesized in the rough ER. • Lysosomes → Membrane bound organelle that houses digestive enzymes that can be used to break down ingested toxins or worn out cell parts.

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 (O 2, CO 2), 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. , diseasecausing organisms)

Respiratory System • Structures: – Nasal cavity, pharynx, trachea, bronchi, lungs • Functions: – Constantly supply the blood with O 2, and remove CO 2 – Regulate blood p. H

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

Why Are Levels of Structure Important? • In this class, we’ll study all levels and see how they work together to create structures and allow them to function. • In essence, the combination of these different yet connected levels allows life to proceed. • But we must also be aware of emergent properties. – Things are often much more than simply a sum of their parts. – Consider a hammer which is made of a head and a handle. Either piece by itself is of little use to drive a nail – but put together, they perform the task quite easily. – Or consider table salt – sodium chloride (Na. Cl). By themselves, chlorine is a poisonous gas and sodium an explosive metal. But when bound together, they create something much, much different. We must be aware of emergent properties as well as reducing structures to their component parts.

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

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], p. H 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)