Anatomy and Physiology: Midterm 1
A chemical reaction occurs when...
A chemical reaction occurs when new bonds are formed or old bonds break between atoms.
Define disease, symptom, and sign; and relate each to homeostatic imbalance.
A disruption of homeostasis can lead to disease and death. Disorder is a general term for any abnormality of function. Disease is a more specific term for an illness characterized by a recognizable set of signs and symptoms. Symptoms are subjective changes in body functions that are not apparent to an observer, for example, headache or nausea. Signs are objective changes that a clinician can observe and measure, for example, fever or rash.
Define a feedback system and list the component parts of a feedback loop.
A feedback system is a cycle of events through which information about the status of a condition is continually monitored and fed back (reported) to a central control region. Any disruption that changes a controlled condition is called a stimulus. A feedback system consists of the three following basic components: A receptor that monitors changes in a controlled condition and sends input as nerve impulses or chemical signals to a control centre The control centre that sets the range of values for the maintenance of a controlled condition, evaluates the input received from the receptors, and generates output commands when needed An effector (a body structure) that receives output from the control centre and produces a response or effect that changes the controlled condition
Describe the components of a typical cell.
A generalized view of the cell is a composite of many different cells in the body. No single cell includes all of the features of the generalized cell. For ease of study, the cell can be divided into three principal parts: Plasma (cell) membrane Cytoplasm: - Cytosol - Organelles (except for the nucleus) Nucleus
Define gland, and differentiate between exocrine and endocrine.
A gland is a single cell or a mass of epithelial cells adapted for secretion. Endocrine glands are ductless; their secretory products (hormones) enter the extracellular fluid and diffuse into the blood. Exocrine glands (sweat, oil, and digestive glands) secrete their products into ducts that empty at the surface of the covering and lining of the epithelium or directly onto a free surface.
Define the term tissue.
A tissue is a group of similar cells that usually have a similar embryological origin and are specialized for a particular function.
Distinguish between endocytosis, pinocytosis, phagocytosis, and exocytosis.
A vesicle is a small membranous sac that forms by budding off from a cell membrane. Two types of vesicular transport are: Endocytosis Exocytosis The two main types of endocytosis are: Phagocytosis Bulk-phase endocytosis Note: Bulk-phase endocytosis, the term used in your textbook, was formerly called pinocytosis. In exocytosis, membrane-enclosed structures called secretory vesicles that form inside the cell fuse with the plasma membrane and release their contents into the extracellular fluid. Note: Table 3.1 provides a summary of the transport of materials into and out of cells that is described in Objectives #3 through #6.
Define the terms active transport (primary and secondary), endocytosis, and exocytosis.
Active transport is an energy-requiring process that moves solutes such as ions, amino acids, and monosaccharides against a concentration gradient. In active transport, which pumps a substance across a plasma membrane against its concentration gradient, the energy derived from adenosine triphopshate (ATP) changes the shape of a transporter protein. In active transport, the energy stored in the form of a sodium or hydrogen ion concentration gradient is used to drive other substances against their own concentration gradients. In the process of endocytosis, molecules or particles that are too large to enter the cell by diffusion or active transport are brought into a vesicle formed from a section of the cell membrane. In the process of exocytosis, membrane-enclosed structures called secretory vesicles, which form inside the cell, fuse with the cell membrane and release their contents into the extracellular fluid.
Discuss the structure and function of adenosine triphosphate (ATP).
Adenosine triphosphate (ATP) is the principal energy-storing molecule in the body. ATP consists of three phosphate groups attached to an adenosine unit, which is composed of adenine and the five-carbon sugar ribose. When energy is liberated from ATP, it is decomposed to adenosine diphosphate (ADP) and phosphorus (P). ATP is manufactured from ADP and P using the energy supplied by various decomposition reactions, particularly that of glucose.
Describe the structure of an atom.
All forms of matter are composed of chemical elements, which are substances that cannot be split into simpler substances by ordinary chemical means. Chemical elements are given letter abbreviations called chemical symbols. Oxygen (O), carbon (C), hydrogen (H), and nitrogen (N) make up 96% of our total body weight. These elements, together with calcium (Ca) and phosphorus (P) make up 98.5% of our total body weight. Structure of Atoms The units of matter of all chemical elements are called atoms. An element is a quantity of matter composed of atoms of the same type. Atoms consist of a nucleus—which contains positively charged protons and neutral (uncharged) neutrons—and negatively charged electrons that move about the nucleus in different energy levels.
List and describe the major processes of life.
All living things have certain characteristics that distinguish them from nonliving things. The life processes of humans include metabolism, responsiveness, movement, growth, differentiation, and reproduction. Metabolism is the sum of all chemical processes that occur in the body, including catabolism and anabolism. Responsiveness is the ability to detect and respond to changes in the external or internal environment. Movement includes the motion of the whole body, individual organs, single cells, or even organelles inside the cells. Growth refers to an increase in size and complexity due to an increase in the number of cells, size of cells, or both. Differentiation is the change in a cell from an unspecialized state to a specialized state. Reproduction refers either to the formation of new cells for growth, repair, or replacement; or the production of a new individual.
Define "anatomy".
Anatomy is the study of structure and the relationships among structures.
For each of the following CTs, describe its structure, name a key body location, and identify its function(s): Blood.
Blood (vascular tissue) consists of a liquid matrix called plasma, and formed elements. Formed elements include erythrocytes, leukocytes, and thrombocytes, and each has specific functions: Red blood cells (erythrocytes) function in transporting respiratory gases. White blood cells (leukocytes) are involved in phagocytosis, immunity, and allergic reactions. Platelets (thrombocytes) function in blood clotting.
What is a body cavity?
Body cavities are spaces within the body that help to protect, separate, and support the internal organs.
Define pH and explain the functioning of buffers.
Body fluids must always contain specific quantities of acids and bases. Biochemical reactions are extremely sensitive to even small changes in acidity or alkalinity. The acidity or alkalinity of a solution is based on the pH scale, which runs from 0 to 14. For example, a pH of 7.0 equals 10-7 or 0.0000001 moles of H+/L which is neutrality. Values below 7 indicate acid solutions ([H+] > [OH-]). Values above 7 indicate alkaline solutions ([H+] < [OH-]). The pH values of different parts of the body are maintained at a fairly constant level by buffer systems, which usually consist of a weak acid and a weak base. The function of a buffer system is to convert strong acids or bases into weak acids or bases. One important buffer system in the body is the carbonic acid-bicarbonate buffer system. Make note of the pH of some substances listed in Table 2.2 on Page 31 of your textbook. In particular, note the pH of distilled water, urine, saliva, and blood.
For each of the following CTs, describe its structure, name a key body location, and identify its function(s): Bone.
Bone (osseous tissue) consists of a matrix containing mineral salts and collagenous fibres and cells called osteocytes. Bone is classified as either compact or spongy, depending on how the matrix and cells are organized. The basic unit of compact bone is the osteon or Haversian system, which consists of four parts. The lamella are concentric rings of matrix that consist of mineral salts that give bone its hardness, and collagen fibres that give bone its strength. Lacunae are small spaces between the lamellae that contain mature bone cells called osteocytes. Canaliculi are minute canals—containing the processes of osteocytes—which provide routes for nutrient and waste transport. A central (Haversian) canal contains the blood vessels and nerves. Spongy bone has trabeculae rather than osteons. Bone supports, protects, helps to provide movement, stores minerals, and houses blood-forming tissue.
List the subcategories of carbohydrates and give examples for each subcategory.
Carbohydrates—including sugars, starches, glycogen, and cellulose—provide most of the energy needed for life. Some carbohydrates are converted to other substances, which are used to build structures and to generate ATP. Other carbohydrates function as food reserves. Carbohydrates are divided into three major groups based on their size: monosaccharides, disaccharides, and polysaccharides. Monosaccharides and Disaccharides: The Simple Sugars Disaccharides are formed from two monosaccharides by dehydration synthesis. Hydrolysis can be used to split disaccharides back into simple sugars. Polysaccharides, the largest carbohydrates, are known as complex carbohydrates; they can include hundreds of monosaccharides. The principal polysaccharide in the human body is glycogen, which is stored in the liver or skeletal muscles. Monosaccharides are joined by dehydration synthesis, and separated by hydrolysis.
For each of the following CTs, describe its structure, name a key body location, and identify its function(s): Hyaline Cartilage, Fibrocartilage, Elastic Cartilage.
Cartilage Cartilage consists of a dense network of collagen fibres and elastic fibres embedded in chondroitin sulfate. Its collagen fibres give it strength, and its chondroitin sulfate gives it resilience. Chondrocytes occur within spaces called lacunae in the matrix. Cartilage is surrounded by a dense irregular connective tissue membrane called the perichondrium. Unlike other connective tissues, cartilage has no blood vessels or nerves (except in the perichondrium). The three major types of cartilage are the following: Hyaline cartilage is the most abundant but weakest type of cartilage. It has fine collagen fibres embedded in a gel-type matrix. It provides flexibility and support, and at the joints, reduces friction and absorbs shock. Fibrocartilage contains bundles of collagen fibres in its matrix. It does not have a perichondrium. Due to its combined strength and rigidity, it is the strongest of the three types of cartilage. Elastic cartilage contains a threadlike network of elastic fibres within the matrix. A perichondrium is present. Elastic cartilage provides strength and elasticity and maintains the shape of certain organs. Cartilage growth is accomplished by interstitial (endogenous—from within) growth and appositional (exogenous—from without) growth.
Discuss the structure and function of enzymes.
Catalysts in living cells are called enzymes. The names of enzymes usually end in the suffix ase. Enzymes are highly specific in terms of the substrate with which they react. Enzymes are extremely efficient with respect to the number of substrate molecules with which they react. Enzymes speed up chemical reactions by increasing the frequency of molecule collisions, lowering the activation energy, and orienting properly the colliding molecules.
Discuss the stages, events, and significance of somatic cell division.
Cell division is the process by which cells reproduce themselves. It consists of nuclear division (mitosis and meiosis) and cytoplasmic division (cytokinesis). Cell division that results in an increase in body cells is called somatic cell division and involves a nuclear division called mitosis, plus cytokinesis. Cell division that results in the production of sperm and eggs is called reproductive cell division and consists of a nuclear division called meiosis, plus cytokinesis. The cell cycle is an orderly sequence of events by which a cell duplicates its contents and divides in two. It consists of interphase and the mitotic phase. During interphase, the cell carries on every life process except division. A cell in interphase shows a distinct nucleus and an absence of chromosomes. The mitotic phase consists of mitosis (or nuclear division) and cytokinesis (or cytoplasmic division). Mitosis is the distribution of two sets of chromosomes, one set into each of two separate nuclei. The stages of mitosis are prophase, metaphase, anaphase, and telophase: During prophase, the chromatin condenses and shortens into chromosomes. During metaphase, the centromeres line up at the exact centre of the mitotic spindle, a region called the metaphase plate or equatorial plane region. Anaphase is characterized by the splitting and separation of centromeres and the movement of the two sister chromatids of each pair toward opposite poles of the cell. Telophase begins as soon as chromatid movement stops; the identical sets of chromosomes at opposite poles of the cell uncoil and revert to their threadlike chromatin form; microtubules disappear or change form; a new nuclear envelope forms; new nucleoli appear; and the new mitotic spindle eventually breaks up. Cytokinesis is the division of the cytoplasm and organelles of a parent cell. The process begins in late anaphase or early telophase with the formation of a cleavage furrow. When cytokinesis is complete, interphase begins.
Describe cilia and flagella.
Cilia and Flagella Cilia are numerous, short, hair-like projections extending from the surface of a cell, which function to move materials over the surface of cells located in the lining of respiratory tract and fallopian tube. Flagella are similar to cilia but are much longer; usually, they move an entire cell. The only example of a flagellum in the human body is the tail of the sperm cell.
Explain how CTs are composed of cells plus an extracellular matrix composed of ground substance and fibres.
Connective tissue consists of the following three basic elements: cells ground substance protein fibres (The latter two combine to form the matrix.)
Describe the general characteristics of connective tissues (CTs) and discuss their major structural differences from epithelial tissue.
Connective tissue is the most abundant and widely distributed tissue in the body. Unlike epithelia, connective tissues do not occur on free surfaces. Unlike epithelium, connective tissue is highly vascular (except for cartilage and tendons). Except for cartilage, connective tissue like epithelium has a nerve supply.
For each of the following CTs, describe its structure, name a key body location, and identify its function(s): Dense connective tissue.
Dense connective tissue contains thicker, denser, and more numerous fibres than loose connective tissue, but considerably fewer cells. Dense regular connective tissue consists of bundles of collagen fibres in a regular, orderly, and parallel arrangement that confers great strength. Dense irregular connective tissue contains collagen fibres that are irregularly arranged; it is found in parts of the body where tensions are exerted in various directions. It usually occurs in sheets, such as the dermis of the skin. It also is found in the heart valves, the perichondrium, the tissue surrounding cartilage, and the periosteum.
Name the four primary adult tissue types, and give a brief description of each.
Depending on their function and structure, the various tissues of the body are classified into the following four principal types: Epithelial tissue covers body surfaces; lines hollow organs, body cavities, and ducts; and forms glands. Epithelial tissue provides external protection for underlying tissue. Connective tissue protects and supports the body and its organs, binds organs together, stores energy reserves as fat, and provides immunity. Muscle tissue is responsible for movement and generation of force. Nervous tissue initiates and transmits action potentials (nerve impulses) that help coordinate body activities, monitors the external environment, and contributes to homeostasis.
Define and contrast the terms diffusion, osmosis, isotonic, hypertonic, hypotonic, and facilitated diffusion.
Diffusion is the random mixing of particles that occurs in a solution as a result of the kinetic energy of the particles. Diffusion is influenced by the following factors: steepness of the concentration gradient temperature size or mass of the diffusing substance surface area diffusion distance Molecules or ions spread spontaneously from regions where they are in higher concentrations toward regions where they are in lower concentrations (i.e., down a concentration gradient), which produces a state of equilibrium. Nonpolar, hydrophobic molecules such as respiratory gases, some lipids, small alcohols, and ammonia can diffuse across the lipid bilayer. This bilayer allows gas exchange, absorption of some nutrients, and excretion of some wastes. Most membrane channels are ion channels, which allow the passage of small, inorganic, hydrophilic ions. Ion channels are selective and specific, and may be gated or open all the time. In facilitated diffusion, a solute binds to a specific transporter on one side of the membrane and is released on the other side after the transporter undergoes a conformational change. This is the process by which glucose enters and leaves most human cells. In living systems, osmosis is the diffusion of water molecules through a selectively permeable membrane. It is the movement of water (the solute) from an area of higher concentration to an area of lower concentration across the membrane. The tonicity of a solution relates to how the solution influences the shape of body cells. In an isotonic solution, red blood cells maintain their normal shape. In a hypotonic solution, red blood cells swell, and undergo hemolysis. In a hypertonic solution, red blood cells shrink, and undergo crenation.
Describe the dorsal body cavity and be able to locate it.
Dorsal Body Cavity The dorsal body cavity is located near the dorsal surface of the body; it has two subdivisions—the cranial cavity and the vertebral canal. The cranial cavity is formed by the cranial bones, which surround and protect the brain. The vertebral (spinal) canal is formed by the bones of the vertebral column, which surround and protect the spinal cord.
How is "energy" defined?
Energy is the capacity to do work.
Five types of connective tissue include:
Five types of CT include: Loose connective tissue Dense connective tissue Cartilage Bone Liquid (blood and lymph)
Describe the features, location, and function of epithelial tissue.
General Features of Epithelial Tissues Epithelial cells are arranged in sheets, in either single or multiple layers. The epithelium consists mostly of packer cells with little extracellular material. In epithelial tissues, many cell junctions are present, providing secure attachments among cells. An epithelial cell has an apical surface and a basal surface attached to a base membrane. Epithelia adhere firmly to nearby connective tissue through a thin extracellular layer called the basement membrane. Epithelia have a nerve supply and a high capacity for renewal (a high mitotic rate). Epithelial tissue is avascular; the exchange of materials between epithelium and adjacent connective tissue is by diffusion. Functions of epithelia include protection, filtration, lubrication, secretion, digestion, absorption, transportation, excretion, sensory reception, and reproduction.
What is the function of the reproductive systems? Components: gonads and associated organs; fallopian tubes, uterus and vagina in females and epididymis, ductus (vas) deferens, and penis in males; also, mammary glands in females.
Gonads produce gametes (sperm or oocytes) that unite to form a new organism and release hormones that regulate reproduction and other body processes; associated organs transport and store gametes, mammary glands produce milk.
What is the function of the cardiovascular system? Components: blood, heart, and blood vessels
Heart pumps blood through blood vessels; blood carries oxygen and nutrients to cells and carbon dioxide and waste away from cells; also helps to regulate acidity, temperature and water content of body fluids; blood components help to defend against disease and mend damaged blood vessels.
What is the function of the integumentary system? Components: skin and structures associated with it, such as hair, nails, and sweat and oil glands.
Helps regulate body temperature, protects the body, eliminates some wastes, helps make vitamin D, detects sensations such as touch, pressure, pain, warmth and cold.
Define homeostasis and explain its importance to survival.
Homeostasis is a condition of equilibrium in the body's internal environment, which is produced by the ceaseless interplay of all the body's regulatory processes. Homeostasis is regulated by the nervous system and endocrine system, acting together or independently. The nervous system detects changes and sends nerve impulses to counteract a disruption. The endocrine system regulates homeostasis by secreting hormones. Nerve impulses cause rapid changes, whereas hormones usually work more slowly.
Define, explain and give examples of positive and negative feedback loops.
If a response reverses the original stimulus, the system is a negative feedback system, for example, the homeostasis of blood pressure (BP). If a response enhances the original stimulus, the system is a positive feedback system, for example, normal childbirth.
Define ion, molecule, compound, and free radical.
If an atom either gives up or gains electrons, it becomes an ion, which is an atom that has a positive or negative charge due to its unequal number of protons and electrons. When two or more atoms share electrons, the resulting combination is called a molecule. A compound is the combination of two or more different atoms, for example, water (H2O). A free radical is an electrically charged atom or group of atoms with an unpaired electron in its outermost shell. Free radicals become stable by either giving up their unpaired electron or by taking on an electron from another molecule. Antioxidants are substances that inactivate oxygen-derived free radicals.
What is the law of conservation of mass?
In a chemical reaction, the total mass of the reactants equals the total mass of the products (the law of conservation of mass).
Differentiate between organic and inorganic compounds.
Inorganic compounds usually lack carbon and are simple molecules; whereas organic compounds always contain carbon and hydrogen, always have covalent bonds, and usually contain oxygen.
Describe membrane transport, and compare and contrast the different processes.
Intracellular fluid is located inside the cell, and extracellular fluid is located outside the cell. The types of extracellular fluid include the following: interstitial fluid plasma lymph Solutes are substances dissolved in a solvent. A concentration gradient is the difference in the concentrations of a substance between two areas (e.g., the amount of water in your cells compared to the amount of water in the lake in which you are swimming, or the amount of sodium ions in extracellular fluid compared to the amount of sodium ions in intracellular fluid). Transport processes are classified according to two criteria: active or passive vesicular Living cells use three passive transport processes, two of which are nonmediated (diffusion through the lipid bilayer and diffusion through a channel) and one that is mediated (facilitated diffusion). Vesicular transport involves the formation of membrane-surrounded vesicles to move materials into or out of the cell by endocytosis or exocytosis.
Describe the different types of chemical bonds, noting their relative strengths.
Ionic Bonds When an atom loses or gains a valence electron, ions are formed. Positively and negatively charged ions are attracted to one another. When this force of attraction holds ions of opposite charges together, an ionic bond results. Cations are positively charged ions. Anions are negatively charged ions. Ionic bonds are weaker than covalent bonds but stronger than hydrogen bonds. (THIS IS DEBATABLE) In general, ionic compounds exist as solids, but in solution, some may dissociate into positive and negative ions. Such a compound is called an electrolyte. Covalent Bonds Covalent bonds are formed when the atoms of molecules share electrons. Covalent bonds are the most common chemical bonds in the body. Covalent bonds can be nonpolar or polar. Covalent bonds are the strongest bonds. The polar covalent bonding of hydrogen to oxygen or nitrogen allows hydrogen bonds to form. Hydrogen Bonds In a hydrogen bond, two other atoms (usually oxygen or nitrogen) associate with a hydrogen atom. Hydrogen bonds are weak and cannot bind atoms into molecules; instead, these bonds serve as links between molecules to provide strength and stability and to help determine the three-dimensional shape of large molecules.
What is an isotope?
Isotopes are different atoms of the same chemical element that have the same number of protons but different numbers of neutrons. A radioactive isotope is unstable and emits radiation (energy).
Identify and describe the subclasses of lipids, and distinguish between saturated and unsaturated fats.
Lipids, like carbohydrates, contain carbon, hydrogen, and oxygen; however, unlike carbohydrates, they do not have a 2:1 ratio of hydrogen to oxygen. Lipids have fewer polar covalent bonds, and thus they are mostly insoluble in polar solvents such as water (they are hydrophobic). However, lipids are soluble in non-polar solvents such as chloroform or alcohol. Triglycerides are the most plentiful lipids in the body and provide protection, insulation, and energy (both immediate and stored). Phospholipids are important membrane components. Steroids have four rings of carbon atoms.
For each of the following CTs, describe its structure, name a key body location, and identify its function(s): Loose connective tissue.
Loose connective tissue consists of all three types of fibres, several types of cells, and a semi-fluid ground substance. Areolar connective tissue is a prime example of loose connective tissue. It presents all of the typical loose connective tissue features. The ground substance aids the passage of nutrients from the blood vessels of the connective tissue to adjacent cells and tissues. It is found in the subcutaneous layer. Adipose tissue is a loose CT consisting of adipocytes, which are specialized for storing triglycerides. It reduces heat loss through the skin; serves as an energy reserve; and supports, protects, and generates considerable heat to help maintain proper body temperature in newborns (brown fat).
Describe lysosomes, peroxisomes, and proteasomes.
Lysosomes are membrane-enclosed vesicles that form in the Golgi complex, and which contain powerful digestive enzymes. Lysosomes function in intracellular digestion, the digestion of worn-out organelles (autophagy), the digestion of cellular contents (autolysis) during embryological development, and extracellular digestion. Peroxisomes are similar in structure to, but are smaller than, lysosomes. Peroxisomes contain enzymes (e.g., catalase) that use molecular oxygen to oxidize various organic substances. A proteasome is a tiny membrane bound sac that contains protease enzymes, which are able to cut proteins.
Define the term epithelial membrane; and discuss the structure, location, and function of its four different types—cutaneous, mucous, serous, and synovial.
Membranes are flat sheets of pliable tissue that cover or line a part of the body. Epithelial membranes consist of an epithelial layer and an underlying connective tissue layer. These membranes include mucous membranes, serous membranes, and the cutaneous membrane or skin. Synovial membranes line joints and contain only connective tissue. Mucous membranes (mucosae) line cavities that open to the exterior, such as the gastrointestinal tract. The epithelial layer of a mucous membrane is an important aspect of the body's defense mechanisms, acting as a barrier to pathogens and a trapping surface for particles. The connective tissue layer of a mucous membrane is called the lamina propria. A serous membrane, or serosa, lines a body cavity that does not open directly to the exterior, and covers the organs that lie within the cavity. Examples of this membrane include the pleura, pericardium, and peritoneum. These membranes consist of parietal and visceral portions. The epithelial layer secretes a lubricating serous fluid that reduces friction between organs and the walls of the cavities in which they are located. Synovial membranes line joint cavities, bursae, and tendon sheaths, and do not contain epithelium; they also secrete a lubricating synovial fluid.
What is metabolism?
Metabolism refers to all the chemical reactions occurring in an organism.
Describe the structure and general function of the nucleus.
Most body cells have a single nucleus; some (red blood cells) have none, whereas others (skeletal muscle fibres) have several. The nucleus includes the nuclear envelope—which is perforated by channels called nuclear pores—the nucleoli, and genetic material (DNA). Within the nucleus are located genes, the hereditary units of cells, which are arranged in single file along the chromosomes. Each chromosome is a long molecule of DNA that is coiled together with several proteins. Human somatic cells have 46 chromosomes arranged in 23 pairs. The various levels of DNA packinging are represented by nucleosomes, chromatin fibres, loops, chromatids, and chromosomes.
Describe the sequence of events involved in protein synthesis.
Much of the cellular machinery is devoted to synthesizing large numbers of diverse proteins. Proteins determine the physical and chemical characteristics of cells. The instructions for protein synthesis are found in the DNA in the nucleus. Protein synthesis involves transcription and translation. Transcription is the process by which the genetic information encoded in DNA is copied onto a strand of RNA called messenger RNA (mRNA), which directs the protein synthesis. Besides serving as the template for the synthesis of mRNA, DNA also synthesizes two other kinds of RNA—ribosomal RNA (rRNA) and transfer RNA (tRNA). The transcription of DNA is catalyzed by RNA polymerase. Translation is the process of reading the mRNA nucleotide sequence to determine the amino acid sequence of the protein. The sequence of translation is as follows: Messenger RNA is associated with ribosomes, which consist of tRNA and proteins. Specific amino acids attach to molecules of tRNA. Another portion of the tRNA has a triplet of nitrogenous bases called an anticodon. A codon is a segment of three bases of mRNA. Transfer RNA delivers a specific amino acid to the codon; the ribosome moves along an mRNA strand as amino acids are joined to form a growing polypeptide.
Compare and contrast the three types of muscle tissue in terms of their structure, control, location in the human body, and function.
Muscle tissue consists of fibres (cells) that are modified for contraction, and thus provide motion, maintenance of posture, and heat production. Skeletal muscle tissue is attached to bones, is striated, and is voluntary. Cardiac muscle tissue forms most of the heart wall, is striated, and is usually involuntary. Smooth (visceral) muscle tissue is found in the walls of hollow internal structures (blood vessels and viscera), is nonstriated, and is usually involuntary. It provides motion (e.g., constriction of blood vessels and airways, propulsion of foods through the gastrointestinal tract, and contraction of the urinary bladder and gallbadder).
Discuss the structure and function of nucleic acid.
Nucleic Acids: Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA) Nucleic acids are huge organic molecules that contain carbon, hydrogen, oxygen, nitrogen, and phosphorus. Deoxyribonucleic acid (DNA) forms the genetic code inside each cell and thus regulates most of the activities that occur in our cells throughout our lifetime. Ribonucleic acid (RNA) carries instructions from the genes in the nucleus of the cell to guide how the ribosomes assemble amino acids into proteins. The basic units of nucleic acids are nucleotides, which are composed of a nitrogenous base, a pentose sugar, and a phosphate group.
What is the function of the muscular system? Components: specifically referring to skeletal muscle tissue, which is muscle usually attached to bones (other muscles include smooth and cardiac).
Participates in bringing about body movements such as walking, maintains posture, and produces heat.
What is the function of the digestive system? Components: organs of the gastrointestinal tract, including the mouth, pharynx (throat), esophagus, stomach, small and large intestines, rectum and anus. Also includes accessory digestive organs that assist in digestive processes such as the salivary glands, liver, gallbladder and pancreas.
Physical and chemical breakdown of food; absorbs nutrients, eliminates solid wastes.
Identify the planes of reference used to depict the structural arrangement of the human body.
Planes are imaginary flat surfaces that are used to divide the body or organs into definite areas. The principal planes include the midsagittal (medial) and parasagittal, frontal (coronal), transverse (cross-sectional or horizontal), and oblique. Sections are the flat surfaces that are created by cutting through body structures. These sections are named according to the plane on which the cut is made, for example, transverse, frontal, and midsagittal. Directional terms are used to precisely locate one part of the body relative to another, and to reduce the length of explanations about these relationships. Commonly used directional terms are dorsal, superior, medial, and distal.
Describe the different forms of energy.
Potential energy is the energy stored by matter due to its position (for example, a ball at the top of a hill). Chemical energy is a form of potential energy stored in the bonds of compounds or molecules. Kinetic energy is the energy associated with matter in motion.
What is the function of the urinary system? Components: kidneys, ureters, urinary bladder, and urethra.
Produces, stores and eliminates urine. Eliminates wastes and regulates volume and chemical composition of blood; helps regulate acid-base balance of body fluids; maintains body's mineral balance; helps regulate red blood cell production
Describe the structure of amino acids and proteins.
Proteins give structure to the body, regulate processes, provide protection, help muscles to contract, transport substances, and serve as enzymes. Amino acids contain carbon, hydrogen, oxygen, and nitrogen. Amino acids are joined together in a stepwise fashion with each covalent bond joining one amino acid to the next, forming a peptide bond. The denaturation of a protein by a hostile environment causes a loss of its characteristic shape and function.
What is the function of the endocrine system? Components: all glands and tissues that produce chemical regulators of body functions, called hormones.
Regulates body activities through hormones transported by the blood to various target organs.
What is the function of the nervous system? Components: brain, spinal cord, nerves, and special sense organs such as the eyes and the ears.
Regulates body activity through nerve impulses by detecting changes in the environment, interpreting the changes, and responding to the changes by bringing about muscular contractions or glandular secretions.
For each of the following CTs, describe its structure, name a key body location, and identify its function(s): Elastic and reticular connective tissue.
Reticular connective tissue consists of a fine interlacing of reticular fibres and reticular cells. It forms the stroma of certain organs, and helps to bind together the cells of smooth muscle. Elastic connective tissue consists of elastic fibres and fibroblasts. It is quite strong and can recoil back to its original shape after being stretched. It is found in lung tissue and elastic arteries.
What is the function of the lymphatic system and immunity? Components: Lymphatic fluid (lymph) and vessels; spleen, thymus, lymph nodes, and tonsils; also cells that carry out immune responses (B cells, T cells, and others).
Returns proteins and fluid to blood; carries lipids from gastrointestinal tract to blood; contains sites of maturation and proliferation of B cells and T cells that protect against disease-causing microbes.
Describe ribosomes.
Ribosomes are tiny spheres that consist of ribosomal RNA and several ribosomal proteins; they occur free (singly or in clusters) or together with endoplasmic reticulum. Ribosomes are the sites of protein synthesis.
Describe the types of chemical reactions.
Synthesis reactions occur when two or more atoms, ions, or molecules combine to form new and larger molecules. These reactions are anabolic, which means that bonds are formed. In a decomposition reaction, a molecule is broken down into smaller parts. These reactions are catabolic, which means that chemical bonds are broken in the process. Note: In oxidation-reduction reactions, electrons are taken from the atom being oxidized by the atom being reduced. Oxidation is the loss of electrons from a molecule, which results in a decrease in the potential energy of the molecule. Reduction is the gain of electrons by a molecule, which results in an increase in the potential energy of the molecule.
Describe the cytoskeleton and the various filaments and tubules that help to make it up.
The Cytoskeleton The cytoskeleton is a network of several kinds of protein filaments that extend throughout the cytoplasm and provide a structural framework for the cell. The cytoskeleton consists of microfilaments, intermediate filaments, and microtubules. Most microfilaments are composed of actin, and function in movement and mechanical support. Intermediate filaments are composed of several different proteins, and function in support and help to anchor organelles such as the nucleus. Microtubules are composed of a protein called tubulin, and help determine cell shape and function in the intracellular transport of organelles and the migration of chromosomes during cell division. Centrosomes are dense areas of cytoplasm that contain the centrioles—the paired cylinders arranged at right angles to one another—that serve as centres for organizing microtubules in interphase cells and the mitotic spindle during cell division.
Describe the anatomical position by using the descriptive and directional terms that refer to body structures, surfaces, and regions.
The anatomical position is a standardized method for observing or imaging the body, which allows precise and consistent anatomical references. In the anatomical position, the subject stands erect facing the observer; his/her upper extremities (arms) are placed at their side; the palms of their hands are turned forward, and their feet are flat on the floor.
Describe the different levels of organization in the human body.
The chemical level -- this level includes atoms, which are the smallest units of matter that participate in chemical reactions -- and molecules, which are two or more atoms joined together. The cellular level -- cells are the basic structural and functional units of an organism. Tissues consist of groups of similarly specialized cells and the substances surrounding them that usually arise from a common ancestor and perform certain special functions. Organs are structures of definite form that have specific functions and are composed of two or more types of tissues. Systems consist of related organs than have a common function.
Discuss the classification scheme for epithelia.
The covering and lining of the epithelia can be classified as a combination of layers and shapes of cells. The name of the specific type of stratified epithelium depends on the shape of the surface cells. Layers are arranged as simple (one layer), stratified (several layers), or pseudostratified (one layer that appears as several). Cell shapes include squamous (flat), cuboidal (cube-like), columnar (rectangular), and transitional (variable).
Define cytoplasm and cytosol.
The cytoplasm consists of cytosol and organelles. Cytosol, the intracellular fluid, is the semifluid portion of cytoplasm that contains inclusions and dissolved solutes. Cytosol is composed mostly of water, plus proteins, carbohydrates, lipids, and inorganic substances. The chemicals in cytosol are either in solution or in a colloidal (suspended) form. Functionally, cytosol is the medium in which many metabolic reactions occur.
Describe the types of ER, the Golgi, and the functions of each.
The endoplasmic reticulum (ER) is a network of membranes that form flattened sacs or tubules called cisterns. Rough ER is continuous with the nuclear membrane and has an outer surface studded with ribosomes. Smooth ER extends from the rough ER to form a network of membrane tubules, but it does not contain ribosomes on its membrane surface. The ER transports substances, stores newly synthesized molecules, synthesizes and packages molecules, detoxifies chemicals, and releases the calcium ions involved in muscle contraction. The Golgi complex consists of four to six stacked, flattened membranous sacs (cisterns) referred to as cis, medial, and trans. The principal function of the Golgi complex is to process, sort, and deliver proteins and lipids to the plasma membrane, lysosomes, and secretory vesicles.
Describe matrix and ground substance.
The matrix is abundant with relatively few cells, and tends to prevent tissue cells from touching one another. The matrix of a connective tissue—which can be fluid, semifluid, gelatinous, fibrous, or calcified—is usually secreted by the connective tissue cells and adjacent cells and determines the qualities of tissues. Immature cells have names that end in blast (e.g., fibroblast, chondroblast), whereas mature cells have names that end in cyte (e.g., osteocyte). Most mature cells have a reduced capacity for cell division and matrix formation, and are mostly involved in maintaining the matrix. The types of cells found in various connective tissues include fibroblasts (which secrete fibres and matrix), macrophages or histiocytes (which develop from monocytes and are phagocytic), mast cells (which are abundant alongside blood vessels and produce histamine), and adipocytes or fat cells (which store energy in the form of fat). The ground substance and fibres, deposited in the space between the cells, comprise the matrix of connective tissue. Substances found in the ground substance include hyaluronic acid, chondroitin sulfate, dermatan sulfate, and keratan sulfate.
Describe the mitochondrion.
The mitochondrion is bound by a double membrane. The outer membrane is smooth, whereas the inner membrane is arranged in folds called cristae. Mitochondria are the site of ATP production in the cell through the catabolism of nutrient molecules. Mitochondria self-replicate using their own DNA.
Identify the major cell of nervous tissue; denote the location of nervous tissue in the body; and discuss its function.
The nervous system is composed of only two principal kinds of cells: neurons (nerve cells) and neuroglia (protective and supporting cells). Most neurons consist of a cell body and two types of processes called dendrites and axons. Neurons are sensitive to stimuli; convert stimuli into nerve impulses; and conduct nerve impulses to other neurons, muscle fibres, or glands. Neuroglia protect and support neurons and are often the sites of tumours of the nervous system.
Describe the structure and function of the plasma membrane.
The plasma membrane is a flexible, sturdy barrier that surrounds and contains the cytoplasm of the cell. The fluid mosaic model describes the structure of the plasma membrane, which is composed of a double layer (bilayer) of phospholipid molecules with many protein molecules dispersed within it. The surfaces of the membrane are "hydrophilic" due to the polar phosphate heads. The internal portion of the membrane is "hydrophobic" due to the non- polar fatty acid tails. Integral proteins are firmly inserted into and extend across the lipid bilayer. Most of these proteins are glycoproteins, which serve as channels (pores), transporters (carriers), receptors (recognition sites), or enzymes. Peripheral proteins lie loosely on the inner and outer surface of the cell membrane, serving as enzymes or cytoskeletal anchors. Membranes are fluid structures, somewhat like cooking oil, because most of the membrane lipids and many of the membrane proteins easily move within the bilayer. Cholesterol serves to stabilize the membrane and reduce membrane fluidity. Plasma membranes are selectively permeable, meaning that some things can pass through and others cannot. The lipid bilayer portion of the membrane is permeable to small, nonpolar, uncharged molecules but impermeable to ions and charged or polar molecules. This bilayer also is permeable to water. Transmembrane proteins that act as channels or transporters increase the permeability of the membrane to molecules that cannot cross the lipid bilayer. Macromolecules are unable to pass through the plasma membrane except by vesicular transport.
For each of the following epithelial tissues, give a structural description, denote a key body location, and identify its function(s): Simple Squamous, Simple Cuboidal, Simple Columnar, Pseudostratified Columnar, Transitional, Stratified Squamous (both keratinized and non-keratinized), Glandular and Stratified Cuboidal.
The simple squamous epithelium consists of a single layer of flat, scalelike cells. It is adapted for diffusion and filtration, and is found in the lungs and kidneys. It is found in parts of the body that are subject to little wear and tear. The endothelium lines the heart and blood vessels. The mesothelium lines the thoracic and abdominopelvic cavities, and covers the organs within them. The simple cuboidal epithelium consists of a simple layer of cube-shaped cells and performs the functions of secretion and absorption. The simple columnar epithelium consists of a single layer of rectangular cells, which can exist in two forms: nonciliated simple columnar epithelium ciliated simple columnar epithelium Nonciliated simple columnar epithelium contains microvilli to increase surface area. Goblet cells secrete mucus. Ciliated simple columnar epithelium contains cells with cilia, motile, hair-like processes that help to move fluids or particles along a surface. Stratified epithelium has at least two layers of cells. It is a more durable and protective tissue. The name of the specific kind of stratified epithelium depends on the shape of the surface cells. Pseudostratified epithelium has only one layer but gives the appearance of many. All cells are attached to the basement membrane, but some do not reach the apical surface. In pseudostratified cilated columnar epithelium, the cells that reach the surface either secrete mucus (goblet cells) or bear cilia that sweep away mucus and trapped foreign particles. Pseudostratified nonciliated columnar epithelium contains no cilia or goblet cells. Stratified squamous epithelium consists of several layers of cells in which the top layer of cells is flat and the deeper layers of cells vary in shape from cuboidal to columnar. The basal cells replicate by mitosis and ultimately work their way to the surface. In keratinized stratified squamous epithelium, a tough layer of keratin (a protein resistant to friction with a capacity to repel bacteria) is deposited in the surface cells. Nonkeratinized stratified squamous epithelium does not contain keratin and remains moist. Stratified cuboidal epithelium is a rare tissue that consists of two or more layers of cube-shaped cells with mainly a protective function. Stratified columnar epithelium consists of several layers of cells of which only the top layer is columnar. It is somewhat rare and functions in protection and secretion. Transitional epithelium consists of several layers of cells; their appearance is variable. It is capable of stretching and thus permits the distention of an organ. It lines the urinary bladder and portions of the ureters and the urethra.
Define "physiology".
The study of how body structures function.
List the major body systems.
The systems of the human body are the integumentary, skeletal, muscular, nervous, endocrine, cardiovascular, lymphatic, respiratory, digestive, urinary, and reproductive.
List the three CT fibre types; and name the types of cells of which CT can be composed.
The three types of fibres embedded in the matrix between the cells of connective tissues are the following: Collagen fibres, composed of the protein collagen, are very tough and resistant to stretching, yet allow some flexibility in the tissue; they are found in bone, cartilage, tendons, and ligaments. Elastic fibres, composed of the protein elastin, provide strength and stretching capacity and are found in the skin, blood vessels, and lungs. Reticular fibres, consisting of collagen and glycoprotein, provide support in the walls of the blood vessels and form a strong, supporting network around fat cells, nerve fibres, and skeletal and smooth muscle fibres.
Describe the role of tissue repair in restoring homeostasis.
Tissue repair is the process of replacing dead or damaged cells. Repair can occur only if inflammation is complete. This repair process will be discussed in greater detail in Chapter 17, which is examined in BIOL 1693 Anatomy and Physiology II. In your textbook page 99, read the "Focus on Wellness" section.
List the regions of the body and the localized areas within each region.
To easily describe the location of the organs, the abdominopelvic cavity can be divided into nine regions by drawing four imaginary lines. In clinical studies, to locate the site of an abdominopelvic abnormality, the abdominopelvic cavity can be divided into quadrants by drawing imaginary horizontal and vertical lines through the umbilicus.
What is the function of the respiratory system? Components: lungs and air passageways such as the pharynx (throat), larynx (voice box), trachea (windpipe), and bronchial tubes leading into and out of the lungs.
Transfers oxygen from inhaled air to blood and carbon dioxide from blood to exhaled air. Also helps regulate acidity of body fluids. The air flowing through vocal cords also allows speech.
Describe the ventral body cavity and be able to locate it.
Ventral Body Cavity The diaphragm subdivides the ventral cavity into an upper thoracic cavity and a lower abdominopelvic cavity. The thoracic cavity contains two pleural cavities and the mediastinum, which includes the pericardial cavity. The pleural cavities enclose the lungs, and the pericardial cavity surrounds the heart. The mediastinum is a broad, median partition between the lungs that extends from the sternum to the vertebral column. It contains everything in the thoracic cavity except the lungs. The abdominopelvic cavity is divided into a superior abdominal and an inferior pelvic cavity.
Discuss the properties of water.
Water is the most important and abundant inorganic compound in all living systems. The most important property of water is its polarity. In the water molecule, the uneven sharing of valence electrons confers a partial negative charge near the single oxygen atom and two partial positive charges near the two hydrogen atoms. Water enables reactants to collide to form products. Water dissolves wastes. Water is the ideal medium for most chemical reactions in the body, and it participates as a reactant or product in certain reactions. Hydrolysis breaks large molecules down into simpler ones by adding a molecule of water. Dehydration synthesis occurs when two simple molecules join together, eliminating a molecule of water in the process. Water has a high heat capacity. It can absorb or release a relatively large amount of heat with only a modest change in its own temperature. The cohesion of water molecules creates a high surface tension, which is a measure of the difficulty involved to stretch or break the surface of a liquid. Water is a major part of mucus and other lubricating fluids.
Define the terms acid, base, salt, and ion.
When the molecules of inorganic acids, bases, or salts dissolve in water, they undergo ionization or dissociation, meaning that they separate into ions. Acids ionize into one or more hydrogen ions (H+) and one or more anions (negative ions). Bases dissociate into one or more hydroxide ions (OH-) and one or more cations (positive ions). Bases are proton acceptors. When dissolved in water, a salt dissociates into cations and anions, neither of which is H+ or OH-.