WhyWWhy are we here? are we here? To learn about human anatomy and physiology. 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 ( generate heat internally) Heterodonty ( teeth w/ different shapes and functions) 3 middle ear bones.

What are humans? Primates Hominids Possess: Bipedal (walk on 2 legs) Opposable thumbs (can you touch your pinky with your thumb?). What advantage does this confer? 2 clavicles (collarbones) 2 mammary glands. Why only 2? Forward facing eyes with stereoscopic vision ( depth perception) Hominids Bipedal (walk on 2 legs) Possess a large brain size/body size ratio

Anatomy formed from 2 words: Defined as the study of… Structure shape, size, and characteristics of the components of the human body. Anatomy formed from 2 words: Ana which means “up or apart” Tomos which means “to cut” Why these two words????

Types of Anatomy Gross Anatomy Study of stuff seen by the naked eye. Microanatomy Study of stuff seen ONLY with the microscope. Histology – study of tissues Cytology – study of individual cells.

Physiology Defined as the study of function Human physiology explains how and why humans (body, anatomical parts) function. How stuff works. How do muscles contract? How do we run? How does our heart beat?

Some Important Themes Biology is hierarchical. Each level of biological structure has emergent properties. The Cell - basic unit of structure and function. Structure and function are correlated at all levels of biological organization!!!!!!!! Regulatory mechanisms create dynamic balance (homeostasis)

Levels of Structure reductionism Organelle 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. Cells have different features organelles macromolecules (e.g., proteins, lipids, carbohydrates and nucleic acids). Organelles – macromolecules macromolecules consist of atoms of various chemical elements.

A Prototypical Cell

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: Functions: - Skin, hair, nails, 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: Functions: The 206 bones of the human body Protects and supports body organs 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?

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

Nervous System Structures: Functions: Brain, spinal cord, and peripheral nerves Functions: Fast-acting control system of the body Monitors internal and external environment responds by initiating muscular or glandular activity

Endocrine System Structures: Functions: 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 other things (stay tuned)

Cardiovascular System Structures: Heart, Blood vessels (arteries, veins, and capillaries) Functions: The heart pumps blood thru the blood vessels. Blood 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: Functions: Nasal cavity, pharynx, trachea, bronchi, lungs Functions: Constantly supply the blood with O2, and remove CO2 Regulate blood pH

Digestive System Structures: Functions: 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: Functions: Kidneys, ureters, bladder, urethra Functions: Removal of nitrogenous wastes Regulation of body’s levels of water, electrolytes, and acidity

Reproductive System Structures: Functions: Male: Female: 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? Understand structure : understand function. Emergent properties. Things are often much more than simply a sum of their parts. We must be aware of emergent properties as well as reducing structures to their component parts.

Can Anatomy & Physiology Be Separated? NOOOOOOO!!!!! Absolutely not! Structure and function are undeniably connected. We cannot divorce them. Can you eat soup with a fork? When you consider the structure of an organ, cell, or anything for that matter you must also consider its function!

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

Necessary Life Functions Maintaining boundaries – the internal environment remains distinct from the external Cellular level – accomplished by plasma membranes Organismal level – accomplished by the skin Movement – locomotion, propulsion (peristalsis), and contractility Responsiveness – ability to sense changes in the environment and respond to them Digestion – breakdown of ingested foodstuffs Metabolism – all the chemical reactions that occur in the body Excretion – removal of wastes from the body Reproduction – cellular and organismal levels Growth – increase in size of a body part or of the organism Differentiation

Survival Needs Water Nutrients - most abundant substance in body - required for metabolic processes - required for transport - regulates body temperature Nutrients - supply energy - supply raw materials Heat - form of energy - partly controls rate of metabolic reactions Oxygen - one-fifth of air - used to release energy from nutrients Pressure - atmospheric pressure – important for breathing - hydrostatic pressure – keeps blood flowing Click the mouse on the page for animated notes.

The Cell’s Environment Cells and the fluid surrounding our cells is in a dynamically stable environment via a process called HOMEOSTASIS.

Homeostasis Maintainence of stable internal conditions in spite of the changing external conditions. 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”

Let’s Thermostat as an Thermostat must first measures current temperature in the house. After the thermostat measures the temperature, it compares the current value to a preset standard value. No difference then there’s nothing to do. 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: Variable  temperature Measuring implement  thermostat Control center  also the thermostat A preset or standard value for the variable Effectors  the air conditioner and furnace Human body has lots of variables maintain at certain precise levels HOMEOSTASIS

Blood Pressure BP is a variable that we’ve got to maintain at a certain level sensory receptors located in the aorta and in the carotid arteries. Measure BP send the info ( input) to a control center in the brain

Blood Pressure Afferent pathway – receptor to control center (brain) 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 – 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 BP Medulla oblongata (the control center) would signal the heart to decrease the force and rate of its contractions; this would decrease BP. 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 Movement of a variable in one direction cause the variable to move in the opposite direction to return the value to the correct level.

Increased BP Sensed by pressure receptors in aortic arch and carotid sinus Input sent via afferent pathway to medulla oblongata BP DECREASES Heart rate & force of contraction decrease Current BP compared with set point and error signal generated Blood vessel diameter increases Output sent along efferent pathway to heart and blood vessels

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! 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?

Homeostasis is DYNAMIC! Homeostatic variables are NOT kept rigidly fixed upon a single value. Certain range Is your body temperature always exactly 98.6°F?

What about Positive Feedback? Is there such a thing?

What about Positive Feedback? Response amplifies or magnifies the stimulus. 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 Feedback in Childbirth

Positive Feedback in Blood Clotting

Dangerous Positive Feedback Rise in body temperature Increase in body heat production Increase in body metabolism

What stops a positive feedback loop?

Water, water everywhere! About 60% of the human body is water 2/3 is found intracellular fluid (ICF) 1/3 is extracellular fluid (ECF) The 2 main types of ECF are: tissue fluid or interstitial fluid Blood! Minor - cerebrospinal fluid (CSF) intraocular fluid

Related Fields of Study Pathology – the study of disease. Why is pathology so important in learning A&P? Embryology - the study of how a single zygote (i.e., a fertilized egg) turns into a fully-fledged human being with trillions of cells. Why is embryology so important to A&P?

Anatomical Position Directional terms Anatomical position is a position in which the body is erect, palms face forward, and thumbs point away from the body. In anatomical position, right and left refer to the right and left sides of the person viewed. In anatomy, anatomical position is always assumed, regardless of the actual position of the body. Directional terms Are used to explain exactly where one body part is in relation to another Superior versus Inferior Anterior versus Posterior Medial versus Lateral Ipsilateral versus Contralateral Proximal versus Distal Superficial versus Deep

Regional Terms: Anterior View Axial – head, neck, and trunk Appendicular – appendages or limbs Specific regional terminology

Regional Terms: Posterior View

Body Planes Sagittal – divides the body into right and left parts Midsagittal or medial – sagittal plane that lies on the midline Parasagittal plane: lies offset from the midline Frontal or coronal – divides the body into anterior and posterior parts Transverse or horizontal (cross section) – divides the body into superior and inferior parts Oblique section – cuts made diagonally organ 1-13

Body Cavities Interactive 1-9

Body Cavities Dorsal cavity divided into ______________ Cranial Cavity Vertebral Canal Ventral cavity is divided into _____________ ____________________ Thoracic Cavity divided into _______________ Pleural Cavity Pericardial Cavity Central area called ______________ mediastinum Abdominopelvic Cavity is divided into _______________ Abdominal Cavity Pelvic Cavity Click the mouse on the page for animated notes. Peritoneal Cavity The thoracic and abdominopelvic cavity are separated by _____________ Diaphragm

Serous Membranes Cavities Visceral layer – covers an organ Parietal layer – lines a cavity or body wall Cavity - between layers contains serous fluid for smooth movement Thoracic Membranes Visceral pleura Parietal pleura Visceral pericardium Parietal pericardium retroperitoneal mesentery Abdominopelvic Membranes Visceral peritoneum Parietal peritoneum Click the mouse on the page for animated notes. Cavities Pleural cavity Pericardial cavity Peritoneal cavity 1-12

Other Body Cavities Oral and digestive – mouth and cavities of the digestive organs Nasal –located within and posterior to the nose Orbital – house the eyes Middle ear – contain bones (ossicles) that transmit sound vibrations Synovial – joint cavities

Abdominal Subdivisions Abdominal Quadrants Nine Abdominal Regions Left Hypochondriac Right Hypochondriac Epigastric region Left Upper Quadrant (LUQ) Right Upper Quadrant (RUQ) Right Lumbar Left Lumbar Umbilical region Right Lower Quadrant (RLQ) Left Lower Quadrant (LLQ) Right Iliac Left Iliac Hypogastric region Click the mouse on the page for animated notes. Practice 1 & 2 Abdominal Subdivisions

Serous Membranes