Why are we here?

1. 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: • What’s a human? • What’s anatomy? • What’s physiology?

2. What are humans? • Organisms are classified as human because they are: • Animals – multicellular, eukaryotic, having no cell wall, heterotrophic • 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.

3. 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

4. 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????

5. 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.

6. 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?

7. Some Important Themes • Biology is hierarchical with each level building on the level below it. • Each level of biological structure has emergent properties. • Cells are an organism’s basic unit of structure and function. • Structure and function are correlated at all levels of biological organization. • Regulatory mechanisms ensure a dynamic balance in living systems.

8. Organelle Levels of Structure Cell • 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 right. Tissue Organ Organ System Organism

9. 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 organellesand 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 atomsof various chemical elements.

10. A Prototypical Cell

11. 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?

12. 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 packaging 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.

13. 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.

15. 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

16. 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)

17. Muscular System • Structures: • The 600+ muscles of the body • Functions: • Locomotion • Manipulation of the environment • Maintaining posture • Thermogenesis (generation of heat)

18. 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

19. Endocrine System • Structures: • Hormone-secreting glands • Pituitary, Thyroid, Thymus, Pineal, Parathyroid, Adrenal, Pancreas, Testes, Ovaries • Functions: • Long-term control system of the body • Regulates growth, reproduction, and nutrient use among other things.

20. 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.

21. 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)

22. Respiratory System • Structures: • Nasal cavity, pharynx, trachea, bronchi, lungs, alveoli • Functions: • Constantly supply the blood with O2, and remove CO2 • Regulate blood pH

23. Digestive System • Structures: • Oral cavity, esophagus, stomach, small intestine, large intestine, rectum, salivary glands, pancreas, liver, gallbladder • Functions: • Ingestion and subsequent breakdown of food (digestion) into absorbable units that will enter the blood for distribution to the body’s cells

24. Urinary System • Structures: • Kidneys, ureters, urinary bladder, urethra • Functions: • Removal of nitrogenous wastes • Regulation of body’s levels of water, electrolytes, and acidity

25. 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

26. 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 (NaCl). 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.

27. 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!

28. How do these organ systems interact?

29. Identify the numbered structures. Integumentary system A CO2 Oxygen F E B D G C H I Unabsorbed matter (feces) Urine (with N wastes)

30. Why do we need all these organ systems? • To perform necessary life functions such as • Maintain boundaries, Movement, Regulation, Nutrition, Metabolism, Excretion, Reproduction, Growth

31. Necessary Life Functions • Maintain boundaries • Movement • Of whole bodies (locomotion) • Of substances within the body (bulk transport, active/passive transport) • Regulation • Responsiveness – ability to sense internal and external changes and react

32. Necessary Life Functions • Nutrition • Ingestion – take in food • Digestion – break down of food • Elimination – release of undigested materials • Metabolism – all the chemical reactions within the body • Release of energy from food (cellular respiration) • Production of body structures (synthesis)

33. Necessary Life Functions • Excretion • Elimination of waste from metabolic reactions • Reproduction • Creation of future generations • Growth • Increase of cell size and number

34. 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

35. Survival Needs • Oxygen • Required for chemical reactions and for energy release from food. • Nutrients • Chemicals for energy and cell building • Includes carbohydrates, proteins, lipids, vitamins, and minerals

36. Survival Needs • Water • 60–80% of body weight • Provides a medium and a reactant for metabolic reactions

37. Water, water everywhere! • About 60% of the human body is water • 2/3 of this water is found within your cells so we refer to it as intracellular fluid (ICF) • The other 1/3 is outside your cells so we call it extracellular fluid (ECF) • The 2 main types of ECF are: • The fluid that surrounds the cells – the tissue fluid or interstitial fluid • Blood! • Minor types of ECF include cerebrospinal fluid and intraocular fluid

38. Survival Needs • Stable body temperature • Temperature must be within a particular range for enzymes to carry out reactions. • Too high or too low temps make cells and their enzymes stop functioning optimally. • Proper atmospheric pressure • Need proper pressure to make organs function properly • Ex: if pressure is too high, lungs can collapse.

39. 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.

40. Homeostasis • Defined as the maintenance of stable internal conditions in spite of changing external conditions. • The body is always in a dynamic state of equilibrium. • Homeostasis must be maintained for normal body functioning and to sustain life • Homeostatic imbalance – a disturbance in homeostasis resulting in disease

41. Homeostasis • How do our bodies maintain the right conditions (i.e., temperature, blood glucoseconcentration, pH etc.)? • Let’s refer to all these conditions as “different variables”

42. Overview of Homeostasis Figure 1.4

43. Maintaining Homeostasis • The human body uses the NERVOUS and ENDOCRINE systems to maintain homeostasis. • Any homeostatic mechanism is going to include the following: • A STIMULUS that produces a change in a variable • A RECEPTOR to sense the change in the variable and to send information to the control center

44. Maintaining Homeostasis • A CONTROL CENTER to determine a set point, analyze incoming information, and determine the appropriate response and send directions to the effector • AN EFFECTOR that reacts to the directions and returns the variable to the homeostatic value or level, thus finally responding to the stimulus.

45. 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.

46. Relate the example to the general model of regulation temperature Weather change • What is the variable? • What is the stimulus? • What is the receptor? What does it do? • What is the control center? What does it do? • What is the effector? What does it do? Thermostat – senses the temperature Thermostat – compares temp to set point and sends message to furnace or AC to turn on Furnace or AC turns on to change the temperature

47. Let’s clarify some stuff. • In the previous example we had a: • Variable  temperature • Measuring implement  thermostat • Control center  also the thermostat • A preset or standard value for the variable • 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 (i.e., blood pressure)

48. Blood Pressure • 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

49. 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!

50. 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.