The Human Body – An Orientation

1. The Human Body – An Orientation • Anatomy – study of the structure and shape of the body and its parts • Physiology – study of how the body and its parts work or function

2. Levels of Structural Organization

3. Necessary Life Functions • Maintain Boundaries • Movement • Locomotion • Movement of substances • Responsiveness • Ability to sense changes and react • Digestion • Break-down and delivery of nutrients • Metabolism – chemical reactions within the body • Production of energy • Making body structures • Excretion • Elimination of waste from metabolic reactions • Reproduction • Production of future generation • Growth • Increasing of cell size and number

4. Survival Needs • Nutrients • Chemicals for energy and cell building • Includes carbohydrates, proteins, lipids, vitamins, and minerals • Oxygen • Required for chemical reactions • Water • 60–80% of body weight • Provides for metabolic reaction • Stable body temperature • Atmospheric pressure must be appropriate

5. Maintaining Homeostasis • The body communicates through neural and hormonal control systems • Negative feedback • Includes most homeostatic control mechanisms • Shuts off the original stimulus, or reduces its intensity • Works like a household thermostat • Positive feedback • Increases the original stimulus to push the variable farther • In the body this only occurs in blood clotting and birth of a baby

6. Exchanging Materials • Cell requires nutrients for energy (food), oxygen, removal of waste products • Materials exchange problems: more difficult to satisfy for larger cells • Surface area limitation • Transport ability dependent on surface area • Metabolic needs determined by volume • Surface-area-to-volume ratio decreases as cell becomes larger • Cells compensate with folded membranes (microvilli) • Diffusion problems • very slow over longer distances • insufficient at distances > 1 mm • Cells remain small

7. The Language of Anatomy • Special terminology is used to prevent misunderstanding • Anatomical position; standing erect, facing you, feet together flat on the floor, the arms slightly raised from the sides with the palms facing forward.

8. Directional Terms • Superior (cranial or cephalad); toward head, above • Inferior (caudal); away from the head, below • Anterior (ventral); front • Posterior (dorsal); behind • Medial; toward the midline, inner side • Lateral; away from the midline, outer side • Intermediate; between • Proximal; close to the origin or the body • Distal; far from the origin or the body • Superficial (external); on or near the surface • Deep (internal)

9. Body Planes

10. Body Planes and Sections • Sagittal — lengthwise (longitudinal) division into right and left parts • Midsagittal (median) section — right and left parts have equal size • Frontal (coronal) — lengthwise (longitudinal) division into anterior and posterior parts • Transverse (horizontal) — cross-sectional division into superior and inferior parts

11. Matter and Energy • Matter – anything that occupies space and has mass (weight) • Energy – the ability to do work • Chemical, Electrical, Mechanical, Radiant • Elements • Fundamental units of matter • 96% of the body is made from four elements • Carbon (C) • Oxygen (O) • Hydrogen (H) • Nitrogen (N) • Atoms • Building blocks of elements

12. Physical and Chemical Changes • Physical change - does not result in change of identity of the matter Example: change of state (boiling, melting, condensing) • Chemical change – alters the identity of matter, producing new substances with different properties Example: burning, cooking, spoiling food

13. Atomic Structure • Nucleus • Protons (p+) • Neutrons (n0) • Outside of nucleus • Electrons (e-) • Atomic number • Equal to the number of protons that the atoms contain • Atomic mass number • Sum of the protons and neutrons

14. Molecules and Compounds • Molecule – two or more like atoms combined chemically • Compound – two or more different atoms combined chemically Chemical Reactions • Atoms are united by chemical bonds • Atoms dissociate from other atoms when chemical bonds are broken

15. Patterns of Chemical Reactions • Synthesis Reactions — two or more smaller atoms or molecules combine to form larger and more complex molecules • Amino acids join together to form a protein • Decomposition Reactions — molecule is broken down into smaller molecules, atoms, or ions by breaking of chemical bonds • Glycogen is broken down to release glucose units • Exchange Reactions — involve both synthesis and decomposition reactions whereby bonds are both made and broken • Glucose and ATP form glucose phosphate and ADP

16. Organic Chemistry • Study of organic compounds • Contain carbon as the principle element • May or may not be formed by living things • Most known compounds are organic Inorganic Chemistry • Study of compounds that do not contain carbon as the principal element

17. Important Organic Compounds • Carbohydrates • Contain carbon, hydrogen, and oxygen • Include cellulose (fiber), sugars and starches • Classified according to size • Monosaccharides – simple sugars • Disaccharides – two simple sugars joined by dehydration synthesis • Polysaccharides – long branching chains of linked simple sugars

18. Lipids (fats) • Large non-polar molecules; carbon and hydrogen atoms far outnumber carbon atoms • Three types • Triglycerides; True fats; used for energy; made of Glycerol and fatty acids • Phospholipids; major component of cell membranes • Steroids; some hormones, cholesterol • Saturated and Unsaturated Fats • Unsaturated fats • usually liquid at room temperature, • Saturated fats • no C-C double bonds, usually solid or almost solid at room temperature, animal fats

19. Proteins and Amino Acids • Proteins; Contain carbon, oxygen, hydrogen, nitrogen, and sometimes sulfur • Polymers made up of amino acids • Include enzymes, hemoglobin, hormones, antibodies • Amino Acids • 20 common amino acids • Different side chains • Amino acids link together • Form polypeptides • Four Levels (Degrees) of Protein Structure • Primary, Secondary, Tertiary, Quaternary

20. Nucleic Acids • Nucleic Acids; constructed of nucleotides • Provide blueprint of life, protein synthesis. • Nucleotide bases • Sugar; 5-carbon simple sugar molecule (either ribose or deoxyribose) • Phosphate group • Nitrogenous base (5 types) Adenine (A), Guanine (G), Thymine (T), Cytosine (C), Uracil (U) • Nucleotide monomers linked together; Sugar and phosphate groups form backbone, Nitrogenous bases stick out • Make DNA and RNA • DNA (Deoxyribose sugar; bases A, T, G, C) • RNA (Ribose sugar; bases A, U, G, C)

21. Deoxyribonucleic Acid (DNA) • Composed of two strands of nucleotide bases • Double helix • Attached between bases according to base pair rule • Human cells contain 46 strands of DNA (chromosomes) • Each strand contains thousands of genes Base Pair Rule • For both DNA and RNA • Guanine always pairs with Cytosine (G C) • In DNA: • Adenine always pairs with Thymine (A T) • In RNA: • Adenine always pairs with Uracil (A U)

22. Ribonucleic Acid (RNA) • Messenger RNA (mRNA) • Single strand copy of portion of DNA coding strand • Formed on the surface of DNA using base pair rule • Uses U-A pairing instead of T-A pairing • After formation, associates with ribosome where genetic message is translated into protein molecule • Ribosomal RNA (rRNA) • Also a RNA copy of DNA • After formation, forms a ribosome • Transfer RNA (tRNA) • Made from different segments of DNA • Responsible for transferring specific amino acids to ribosome for protein manufacture

23. Adenosine triphosphate(ATP) • Universal chemical energy used by all cells • Energy is released by breaking high energy phosphate bond • High-energy phosphate bonds broken by hydrolysis releases energy for work such as muscle contraction • ATP is replenished by oxidation of food fuels

24. Cell and Tissues • Carry out all chemical activities needed to sustain life • Cells are the building blocks of all living things • Cells are not all the same; Lots of shapes and sizes • Tissues are groups of cells that are similar in structure and function

25. Cell Organization

26. The Nucleus • Control center of the cell • Contains genetic material (DNA); Genetic repository for ~ 35,000 genes • Genes control the synthesis of proteins in each cell. • Three regions • Nuclear membrane • Nucleolus • Chromatin Figure 3.1b

27. The Plasma Membrane • Selectively-permeable lipid bilayer • Hydrophilic (“water-loving”) polar heads • Hydrophobic (“water-hating”) nonpolar tails • Specializations of the Plasma Membrane • Microvilli; increases the surface area for absorption • Tight Junctions; no seeping allowed – intestinal cells • Desmosomes; even water cannot pass through - skin cells • Gap Junctions – material exchanged is allowed – heart cells

28. Cytoplasmic Organelles • Mitochondria—ATP replenishment • Ribosomes—protein synthesis • Endoplasmic Reticulum (ER)—network within cytoplasm • Rough ER • Smooth ER • Golgi Apparatus—modify and direct cellular protein transport • Secretory Vessels • Lysosomes—digestive enzymes • Peroxisomes—detoxification using molecular oxygen • Free Radicals—highly-reactive chemicals • Cytoskeleton—internal framework • Intermediate filaments, Microfilaments, Microtubules • Centrioles—direct formation of mitotic spindle • Other Structures in Specialized Cells • Cilia, Flagella

29. Membrane Transport • Passive Transport Processes: Diffusion and Filtration; does NOT require energy • Diffusion—molecules move down concentration gradient • Simple Diffusion • Osmosis • Facilitated Diffusion • Filtration—nonselective hydrostatic pressure gradient • Active Transport Processes—ATP pumps against gradient; requires energy • Solute Pumping—simultaneous sodium-potassium pump • Bulk Transport • Exocytosis, • Endocytosis • Phagocytosis (cell eating) • Pinocytosis — Fluid-Phase Endocytosis (cell drinking)

30. Cell Division (Mitosis) • Cell Life Cycle • Interphase – cell grows and DNA doubles itself • Cell Division • Preparations: DNA Replication • DNA double-helix unwinds • Each strand acts as template • Events of Cell Division • Mitosis—division of nucleus • Prophase—nuclear envelop disappears • Metaphase—chromosomes cluster and align along equator • Anaphase—chromosomes pulled toward opposite poles • Telophase—nuclear envelop reforms • Cytokinesis—division of cytoplasm

31. Protein Synthesis • Genes: The Blueprint for Protein Structure • The Role of RNA • Messenger RNA (mRNA) • Transfer RNA (tRNA) • Ribosomal RNA (rRNA) • Transcription— information transfer from DNA base sequence onto complementary mRNA base sequence • Codon—three-base sequence on mRNA • Translation— base sequence “language” of nucleic acid becomes “language” of proteins within cytoplasm • Anticodon—three-base sequence on tRNA

32. Circulatory System: Blood • Transports molecules, cells, heat • respiratory gases, nutrients, waste products, antibodies, hormones • Cells and molecules suspended in plasma • Erythrocytes (red blood cells): transport O2 and CO2 • Contain hemoglobin (iron-containing molecule binds to oxygen) • White blood cells (WBC): immune system • Lymphocytes – produce antibodies (immunoglobulins) that attach to antigens (immunogens) • Phagocytes (neutrophils, monocytes) – engage in phagocytosis engulfing harmful materials (phagocytes) • Macrophages • large, most active of phagocytes, develop from monocytes • Eosinophils – destroy multicellular parasites • Basophils – involved in inflammation response • Platelets • Fragments of specific type of WBC • Important in blood clotting

34. The Human Heart 4 chambers • Right and left atria • Collect blood from veins and empty into ventricles • Right and left ventricles • Pump blood through arteries Right and left side • Right (pulmonary circulation) • Receives blood from body; pumps through pulmonary artery to lungs where exchange of O2 and CO2 take place • Blood returns from lungs to left atrium • Left (systemic circulation) • Receives blood from lungs delivers through aorta to body • Blood returns to right atrium via veins (superior vena cava, inferior vena cava) Sets of valves • Atrioventricular valves • Allows blood to flow from atria to ventricles • Prevents opposite flow • Semilunar valves • In aorta, pulmonary arteries • Prevents blood from flowing back into ventricles

35. The Human Heart 4 chambers • Right and left atria • Collect blood from veins and empty into ventricles • Right and left ventricles • Pump blood through arteries Right and left side • Right (pulmonary circulation) • Receives blood from body; pumps through pulmonary artery to lungs where exchange of O2 and CO2 take place • Blood returns from lungs to left atrium • Left (systemic circulation) • Receives blood from lungs delivers through aorta to body • Blood returns to right atrium via veins (superior vena cava, inferior vena cava) Sets of valves • Atrioventricular valves • Allows blood to flow from atria to ventricles • Prevents opposite flow • Semilunar valves • In aorta, pulmonary arteries • Prevents blood from flowing back into ventricles

36. Arteries, Veins, Capillaries Arteries • Carry blood away from heart to body • Systolic blood pressure: heart contracting • Diastolic blood pressure: heart relaxing • Walls – thick, muscular, elastic • Blood flow from aorta to smaller arteries (arterioles) to capillaries • Capillaries: • tiny, thin walled tubes • located near each cell • Allows molecular exchange by diffusion • Lymph leaks through small holes Veins • Collect blood from capillaries and return it to heart • Pressure in veins very low

37. Lymph • Produced when blood pressure forces water and dissolved molecules through walls of capillaries • Returns to circulatory system by lymphatic system

38. Skin • Largest organ • Provides impermeable barrier • Removes heat • Three layers • Epidermis (surface) • Cornified (outer) layer • Provides toughness, impermeability • Prevents loss of water and entry of microorganisms • Germinating layer • Produce cells by mitosis that migrate toward surface and replenish cornified layer • Cells produce keratin (hair, nails) • Melanin (pigment) • Dermis • Contains connective tissue fibers, blood vessels, nerve endings • Subcutaneous layers • Contains fat cells, blood vessels, nerve endings and connective tissue fibers, which bind skin to underlying tissues (muscles) • Glands • Oil, sweat, scent, mammary

39. Respiratory System • Nose, mouth, throat • Clean air, modify humidity, temperature • Lungs • Organs in which gas exchange takes place between air and blood • Tubes conducting air to lungs • Trachea • Contain cells with cilia • Two bronchi • Deliver air to smaller branches • Bronchioles • Alveoli • Tiny sacs: gas exchange takes place between air and blood • Diaphragm • Movementcauses breathing

40. Digestion System Begins in the mouth • Teeth, tongue • Salivary glands (3) • Produce saliva • contains salivary amylase • enzyme initiates starch breakdown Passes to the stomach • Pharynx (walls of throat) • Bolus stimulates nerve endings causing contraction of esophagus which transports bolus to stomach • Epiglottis • Covers opening to trachea to prevent food entering lungs

41. Digestion System In the stomach • Gastric juice • Contains enzymes (pepsin), hydrochloric acid • pH ~2 • Mixing results in chyme • Chyme leaves stomach through valve pyloric sphincter and enters the small intestine

42. Digestion System Small intestine (duodenum) • Secretes hormones that regulate release of food from stomach and secretions from pancreas and liver Pancreas • Produces digestive enzymes • Secretes bicarbonate ions • neutralize duodenum to pH~8 Liver • Secretes bile Bile • Stored in gall bladder before release in duodenum • Emulsifies fat particles Large intestine • Reabsorbs water, saliva, gastric juice, bile, pancreatic secretions, intestinal juices • Home to bacteria

43. Nutrition Uptake Organic molecules must be absorbed into circulatory system through intestines • Small intestine ~3 meters in length Lined with villi • Tiny projections • Increase surface area • Total intestinal surface area ~250 m2 • Contain several capillaries and lacteal (branch of lymphatic system)

44. The Skelton • Provides support while allowing movement • Furnishes protection for organs, brain, spinal cord

45. Nutrients Molecules consumed to maintain the body • Vitamins • Organic molecules • Can’t be manufactured by body • Required to assist enzymes • Minerals • Inorganic molecules used in small amounts for variety of purposes • Water • Most common molecule in body • Continually replaced Carbohydrates • Sugars and starches • Provide energy • 4 kilocalories/gram Fats • Broken down into smaller units that can enter the Krebs cycle • Provide energy • 9 kilocalories/gram Proteins • Polymers of amino acids • Important in growth, structure of cells • Contain energy • 4 kilocalories/gram • More difficult to break down than fats or carbohydrates

46. Measuring the Energy in Food • A calorie is the amount of heat needed to increase the temperature of one gram of water one degree Celsius • A kilocalorie (kcal) is the amount of heat needed to increase the temperature of one kilogram of water one degree Celsius • Measure of food energy (Calorie) kilo =1000 • kilocalorie has1000 times more heat energy than a calorie

48. Excretory System • Waste elimination • Urea, hydrogen ions, water, salts • Kidneys • Produce urine which flows through ureters to urinary bladder and exits the body through the urethra • Consists of millions of nephrons • Regions of the nephron • Bowman’s capsule • Proximal convoluted tubule • Loop of Henle • Distal convoluted tubule • Large surface area • Filtration • Reabsorption • Secretion

49. Control Mechanisms • Homeostasis – process of maintaining a constant internal environment as a result of monitoring and modifying the function of various systems • Nervous, endocrine systems • Stimulus – detectable change in environment • Light, sound, pain • Response – reaction to stimulus

50. Neurons (Nerve Cells) • Soma (cell body) • Nucleus • Nerve fibers • Axons • Carry information away from cell body • Usually 1 axon • Dendrites • Carry information toward cell body • Usually several dendrites • Neurons arranged in two different systems • Central nervous system (CNS): brain, spinal cord • Receives input from sense organs, interprets information, generates responses • Peripheral nervous system: bundles of axons, dendrites (nerves) • Motor neurons carry messages from CNS to muscles and glands • Sensory neurons carry impulses from sense organs to CNS