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COMMON TEST REVISION Human Biosciences 1.1 Official (Closed) - Non Sensitive The Language of Anatomy Anatomical position Standard body position used to avoid confusion Terminology refers to this position regardless of actual body position...

COMMON TEST REVISION Human Biosciences 1.1 Official (Closed) - Non Sensitive The Language of Anatomy Anatomical position Standard body position used to avoid confusion Terminology refers to this position regardless of actual body position Stand erect, feet parallel, arms hanging at the sides with palms facing forward and thumbs pointing away from the body Official (Closed)Table - Non1.1Sensitive Orientation and Directional Terms (1 of 3) © 2018 Pearson Education, Ltd. Official (Closed)Table - Non1.1Sensitive Orientation and Directional Terms (2 of 3) © 2018 Pearson Education, Ltd. Official (Closed)Figure - Non1.5 The planes of the body—median, frontal, and transverse—with corresponding MRI scans. Sensitive (a) Median (midsagittal) (b) Frontal (coronal) plane (c) Transverse plane Vertebral Right Left column lung Heart lung Liver Aorta Pancreas Spleen Rectum Intestines Liver Stomach Spleen Subcutaneous Spinal fat layer cord © 2018 Pearson Education, Ltd. Official (Closed) - Non Sensitive Abdomen and pelvic region Official (Closed) - Non Sensitive Dorsal and ventral body cavities and their subdivisions. Cranial Cranial cavity cavity (contains brain) Vertebral cavity Superior mediastinum Dorsal body Thoracic cavity cavity Pleural (contains cavity heart and Pericardial lungs) cavity within the mediastinum Vertebral cavity Ventral body (contains spinal cavity Diaphragm (thoracic and cord) abdominopelvic cavities) Abdominal cavity (contains digestive Abdomino viscera) pelvic cavity Pelvic cavity (contains urinary Dorsal body cavity bladder, reproductive organs, and rectum) Ventral body cavity Lateral view Anterior view Official (Closed) - Non Sensitive Homeostatic Controls Receptor Control center Effector (sensor) Determines set point at which Receives output from control variable is maintained center Monitors environment Receives input from receptor Provides the means to respond Responds to stimuli (things that cause changes in controlled Response either variables) Determines appropriate response reduces stimulus (negative feedback) or enhances stimulus (positive feedback) Official (Closed) - Non Sensitive Examples of Negative Feedback Mechanism Body Temperature Control: The hypothalamus, located in the brain, plays a central role in maintaining body temperature. When the hypothalamus detects that the body is too hot, it initiates a response to reduce the temperature back to the correct level. The response involves sweating, which helps dissipate heat through evaporation from the skin. Once the body temperature returns to the desired set point (usually around 98.6°F / 37.0°C), sweating stops. Conversely, if the body gets too cold, the hypothalamus triggers shivering to generate heat and raise the temperature. Remember, negative feedback loops aim to bring the system back to its set point by opposing the initial stimulus. In the case of body temperature, this mechanism ensures that we maintain a stable internal environment for optimal health and function. Official (Closed) - Non Sensitive Examples of Negative Feedback Mechanism Insulin and Blood Sugar Regulation: When blood sugar rises, receptors in the body detect this change. In response, the control center (specifically the pancreas) secretes insulin into the blood. Insulin acts on various cells, promoting the uptake of glucose from the blood into tissues (such as muscle and liver cells). As a result, blood sugar levels decrease, returning to homeostasis. Once blood sugar reaches the desired set point, the pancreas stops releasing insulin. Official (Closed) - Non Sensitive Examples of Negative Feedback Mechanism In the respiratory system, negative feedback mechanisms play a crucial role in maintaining homeostasis. Chemoreceptor Regulation of Breathing: Chemoreceptors detect the levels of carbon dioxide (CO₂) in the blood by monitoring the concentrations of hydrogen ions (H⁺). An increase in CO₂ concentration leads to a decrease in blood pH due to the production of H⁺ ions from carbonic acid. In response to decreased blood pH, the respiratory centre (located in the medulla oblongata) sends nervous impulses to the external intercostal muscles and the diaphragm. This results in an increase in the breathing rate and the volume of the lungs during inhalation. Hyperventilation causes alkalosis, leading to a feedback response of decreased ventilation (to increase CO₂ levels). Conversely, hypoventilation causes acidosis, resulting in increased ventilation (to remove excess CO₂). Any situation with hypoxia (too low oxygen levels) triggers a feedback response that increases ventilation to enhance oxygen intake. Additionally, vomiting causes alkalosis, and diarrhoea causes acidosis, both leading to appropriate respiratory feedback responses. Official (Closed) - Non Sensitive CVS_1d The heart is a double pump, each side supplying its own circuit. Pulmonary circulation: Blood flows from the right side of the heart to the lungs and back to the left side of the heart HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1d Pulmonary circulation From the right ventricle, blood leaves Blood leaves right ventricle the heart as it passes through the pulmonary semilunar valve into the Pulmonary valve (pulmonary semilunar valve) pulmonary trunk Pulmonary trunk splits into right and Pulmonary trunk left pulmonary arteries, which carry blood to the lungs In the lungs, blood picks up oxygen Right and left pulmonary arteries and drops off carbon dioxide Oxygen-rich blood returns to the Respiratory capillaries (where gas exchange occurs) heart through the four pulmonary veins Right and left pulmonary veins Flows into left atrium HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1d Systemic circulation: Blood flows from the left side of the heart to body tissues, and back to the right side of the heart HBS1_School of Health Sciences  Official (Closed) - Non Sensitive CVS_1d Systemic circulation Blood leaves left ventricle, flows through: Oxygen-rich blood returns to the heart through the four pulmonary veins Aortic valve (aortic semilunar valve) Blood enters the left atrium and travels through the bicuspid valve into the left Ascending aorta and aortic arch ventricle From the left ventricle, blood leaves the heart arteries via the aortic semilunar valve and aorta Reach the tissues were Substances move to Numerous branches to capillary beds in the tissues and from the blood and tissue cells through capillary walls Systemic veins Deoxygenated blood will travel via superior and inferior venae cavae reach the right Inferior and superior venae cavae, coronary sinus atrium Flows into right atrium HBS1_School of Health Sciences Official (Closed) - Non Sensitive CVS_1d HBS1_School of Health Sciences  Official (Closed) - Non Sensitive Coronary Circulation Blood in the heart chambers does not nourish the myocardium The heart has its own nourishing circulatory system consisting of: Coronary arteries—branch from the aorta to supply the heart muscle with oxygenated blood Cardiac veins—drain the myocardium of blood Coronary sinus—a large vein on the posterior of the heart, receives blood from cardiac veins Blood empties into the right atrium via the coronary sinus HBS1_School of Health Sciences Official (Closed) - Non Sensitive HBS1_School of Health Sciences Official (Closed) - Non Sensitive HBS1_School of Health Sciences Official (Closed) - Non Sensitive Cardiac Output Cardiac output (CO) Stroke volume (SV) Amount of blood pumped by each Volume of blood pumped by side (ventricle) of the heart in one each ventricle in one minute contraction (each heartbeat) CO = HR  SV About 70 ml of blood is pumped CO = HR (75 beats/min)  SV (70 out of the left ventricle with ml/beat) each heartbeat CO = 5250 ml/min = 5.25 L/min Heart rate (HR) Typically, 75 beats per minute Mader, Sylvia S.Windelspecht, Michael. (©2020) Human biology /New York, NY : McGraw-Hill, HBS1_School of Health Sciences Official (Closed) - Non Sensitive HBS1_School of Health Sciences Official (Closed) - Non Sensitive Blood pressure naturally fluctuates throughout the day due to various factors. Daily Pattern: White-Coat Syndrome: Medications and Diet: Blood pressure follows a daily Some people experience white- Certain medications (both over- rhythm. Typically, it starts to rise a coat syndrome, where their blood the-counter and prescription) can few hours before you wake up in pressure temporarily spikes during impact blood pressure. the morning. a doctor’s appointment due to Caffeine from drinks and foods can Throughout the day, it continues to anxiety. temporarily elevate blood pressure. increase, peaking around midday. At home, their readings may be Foods high in tyramine (found in In the late afternoon and evening, normal, but the clinic visit can aged foods) may also affect blood blood pressure typically drops. cause a higher reading. pressure. HBS1_School of Health Sciences Official (Closed) - Non Sensitive Blood pressure naturally fluctuates throughout the day due to various factors. Normal Fluctuations: Stress, exercise, and sleep can all influence blood pressure. During physical activity or emotional stress, blood pressure may temporarily rise. Conversely, during rest or relaxation, it may decrease. When you engage in physical activity, your blood pressure temporarily rises. This increase is typically temporary and should return to normal after you finish exercising. During exercise, your heart pumps more efficiently. Aerobic exercises like swimming, cycling, and running put additional demands on your cardiovascular system. Your muscles require more oxygen during exercise, leading to faster breathing and increased heart rate. As a result, systolic blood pressure (measured when your heart beats) rises. It’s normal for systolic pressure to reach between 160 and 220 mm Hg during exercise. HBS1_School of Health Sciences  Composition of Blood Blood is a liquid connective tissue made of formed elements (cells and cell fragments) suspended in plasma. formed plasma Blood elements Formed elements are produced in the red bone marrow: Red blood cells/erythrocytes (RBCs). White blood cells/leukocytes (WBCs). Platelets/thrombocytes.  Plasma Consists of 91% water and 9% salts and organic molecules. Solutes help maintain the osmotic pressure of blood. Salts act as buffers. Other solutes: nutrients, wastes, hormones. Plasma proteins are the most abundant organic molecules. Most are produced by the liver. Create osmotic pressure in the Mader, Sylvia S.Windelspecht, Michael. (©2020) Human biology /New York, NY : McGraw-Hill blood. Three major types  Plasma Three major types of plasma proteins: Albumins Globulins Fibrinogen Most abundant Some transport Inactive; when of the plasma substances in activated, proteins. the blood. forms blood Contribute to Others, such clots. osmotic as gamma pressure more globulins, fight than others. pathogens. Transport molecules in the blood.  Red Blood Cells - Erythrocytes Main function of the RBC is to carry oxygen Biconcave shape increases surface area flexibility to squeeze through narrow capillaries Anucleate (no nucleus) + no organelles in the cytoplasm Contain the protein hemoglobin (Hb). Martin. (2017) Fundamentals of Anatomy and Physiology  Red Blood Cells & hemoglobin (Hb) Hemoglobin (Hb) is a iron (Fe)- containing protein that binds oxygen. Hemoglobin is the reason for RBCs, and therefore blood, to be red. The heme / iron portion of Hb binds up to four oxygens. When bound to oxygen, Hb is called oxyhemoglobin. When oxygen leaves Hb in the tissues, it is called deoxyhemoglobin. Mader, Sylvia S.Windelspecht, Michael. (©2020) Human biology /New York, NY : McGraw-Hill  The production of red blood cells. Occurs in the red bone marrow. As RBCs are produced, they lose their nucleus and most organelles. Without a nucleus, can’t make proteins for cell repair. Therefore, only live about 120 days. Old, worn-out cells are removed from circulation by macrophages in the liver and spleen. The biconcave shape / disc shape allows them to squeeze through small capillaries and allows for maximum surface area (for gas diffusion).  The production of red blood cells. Erythropoietin (EPO). A hormone produced by the kidneys when oxygen levels of the blood are low. Stimulates the bone marrow to produce more red blood cells. Mader, Sylvia S.Windelspecht, Michael. (©2020) Human biology /New York, NY : McGraw-Hill  Haemostasis Stoppage of bleeding resulting from a break in a blood vessel Haemostasis involves three phases: 1. Vascular spasms 2. Platelet plug formation 3. Coagulation (blood clotting)  Haemostasis Vascular spasms – Vasoconstriction causes blood vessel to spasm – Spasms narrow the blood vessel, decreasing blood loss Mader, Sylvia S.Windelspecht, Michael. (©2020) Human biology /New York, NY : McGraw-Hill  Haemostasis Platelet plug formation – Collagen fibers are exposed by a break in a blood vessel – Platelets become “sticky” and cling to fibers – Anchored platelets release chemicals to attract more platelets – Platelets pile up to form a platelet plug (white thrombus) Mader, Sylvia S.Windelspecht, Michael. (©2020) Human biology /New York, NY : McGraw-Hill  Haemostasis Coagulation – Within the hour, serum is squeezed from the clot as it retracts Serum is plasma minus clotting proteins Mader, Sylvia S.Windelspecht, Michael. (©2020) Human biology /New York, NY : McGraw-Hill  ABO Blood Groups Antigen —a foreign substance, often a glycoprotein, that stimulates an immune response. Blood types are determined by the presence and/or absence of two antigens, type A and type B on the surface of RBC: Type A blood has the A antigen (glycoprotein). Type B has the B antigen. Type AB has the A and the B antigens. Type O has neither. Rh positive notation indicates the presence of the Rh antigen; Rh negative, the absence of it  ABO Blood Groups ABO blood groups, continued. In type A blood, anti-B antibodies are found in the plasma In type B blood, anti-A antibodies are found in the plasma. In type AB blood, neither of these are found in the plasma. In type O blood, both are found in the plasma. Antibodies are specific and bind only to the antigen they are made for. Unlike anti-A and anti-B antibodies, anti-Rh antibodies only develop in a person after they are exposed to the Rh factor. ABO Blood Groups Official (Closed) - Non Sensitive Nasal cavity Oral cavity Nostril Pharynx Larynx Trachea Left main Right main (primary) (primary) bronchus bronchus Left lung Right lung Diaphragm HBS1_Apr20 Official (Closed) - Non Sensitive Respiratory defense system Mucociliary escalator Flow of mucus/trapped debris Sticky mucus produced by mucous cell and mucous glands Traps debris particles Moved by beating cilia Swept toward pharynx Swallowed (to acids in stomach) or coughed out Alveolar macrophages Engulf small particles that reach lungs HBS1_Apr20  Official (Closed) - Non Sensitive Larynx (Voice Box) Epiglottis A spoon-shaped flap of elastic cartilage Protects the superior opening of the larynx Routes food to the posteriorly situated esophagus and routes air toward the trachea When swallowing, the epiglottis rises and forms a lid over the opening of the larynx HBS1_Apr20  Official (Closed) - Non Sensitive The Alveoli The lungs have about 300 million alveoli. Each alveolar sac is surrounded by blood capillaries. The walls of the sac and the capillaries are both made of simple squamous epithelium. Gas exchange occurs between air in the alveoli and blood in the capillaries. Oxygen diffuses across the alveolar wall and enters the bloodstream, and carbon dioxide diffuses from the blood into the alveoli. The alveoli are lined with surfactant, a film of lipoprotein that lowers the surface tension of water and prevents the alveoli from closing. Official (Closed) - Non Sensitive Alveolar duct Alveoli Respiratory Alveolar duct bronchioles Terminal bronchiole Alveolar sac (a) Diagrammatic view of respiratory bronchioles, alveolar ducts, and alveoli HBS1_Apr20  Official (Closed) - Non Sensitive Structure of Alveoli Primary cells are pneumocytes type1: Unusually thin simple squamous epithelium Roaming alveolar macrophages (dust cells): Patrol epithelium, phagocytizing particles in alveoli Pneumocytes type 2: Produce surfactant, a liquid that helps to keep alveoli open by reducing surface tension HBS1_Apr20 Official (Closed) - Non Sensitive Pulmonary ventilation The lungs lie within the sealed thoracic cavity. Rib cage—top and sides of the thoracic cavity. Intercostal muscles—between the ribs. Diaphragm—floor of the thoracic cavity. Primary respiratory muscles: The diaphragm External intercostals Accessory respiratory muscles: the sternocleidomastoid, the pectoralis major, the trapezius Activated when respiration HBS1_Apr20 increases significantly Official (Closed) - Non Sensitive Control of Ventilation Breathing is controlled by the nervous system and by certain chemicals. Nervous control of breathing Neural centers that control rate and depth are located in the medulla oblongata and pons – in the brain stem. Respiratory control center in the brain automatically sends out nerve signals to the diaphragm and the external intercostal muscles of the rib cage, causing inspiration to occur.  Official (Closed) - Non Sensitive Nervous Control of Breathing Although the respiratory center automatically controls the rate and depth of breathing, it is influenced by the nervous system. We can voluntarily change our breathing pattern for speaking, singing, eating, swimming underwater. Following forced inspiration, stretch receptors in the airway walls initiate inhibitory nerve impulses that stop the respiratory center from sending out nerve signals and overstretching the lungs. Official (Closed) - Non Sensitive Chemical Control of Breathing Cells produce CO2 during cellular respiration. CO2 then enters the blood, where it combines with water, forming an acid that breaks down and gives off hydrogen ions. These H+ decrease the pH of the blood. Chemoreceptors—sensory receptors that are sensitive to the chemical composition of body fluids. Two sets of chemoreceptors sensitive to pH can cause breathing to speed up. One set is in the medulla oblongata of the brain stem. The other set is the carotid bodies of the carotid arteries, and aortic bodies of the aorta. Official (Closed) - Non Sensitive Production of CO2 during cell respiration Formation of acid and decreased pH Activation of Chemoreceptors Respiratory center increases the rate and depth of breathing Remove CO2 from the blood. HBS1_Apr20  Classification of cells Cells are classified into two categories: prokaryotes and eukaryotes. Prokaryotic cell (prokaryotes) Eukaryotic cell (eukaryotes) Lack a nucleus. Have a nucleus. Include two groups of Include animals, plants, fungi, bacteria: eubacteria & protists. archaebacterial.  Eukaryotic cell o Plasma membrane. Surrounds the cell. o Nucleus oCytoplasm: the semifluid substance inside the cell. Includes organelles (internal compartments with specialized functions).  The Plasma Membrane A biological membrane that separates the interior of a cell from its outside environment. The plasma membrane is made up of two layers of lipids: known as the lipid bi-layer. The lipids are very fluid and dynamic layers, where proteins may be embedded in either side or even through the membrane. Fluid-mosaic model Functions of the plasma membrane Physical isolation Barrier Regulation of Ions and nutrients enter exchange of Wastes eliminated and cellular products substances with the released environment Sensitivity to the Detect extracellular fluid composition environment and chemical signals Structural support Anchors cells and tissues  The Plasma Membrane Made up of: Proteins Phospholipids Glycoprotein & Glycolipids Cholesterol Outside the cell (extracellular) Inner part of the cell (intracellular) Boundless.com. License: CC BY-SA: Attribution-ShareAlike  Plasma Membrane ◼Membrane lipids – Phospholipidbilayer ◼ Hydrophilic heads—face outward on both sides, toward watery environments ◼ Hydrophobic fatty-acid tails— inwards, sandwiched between the heads ◼ Barrier to ions and water-soluble compounds - Cholesterol helps to maintain cell membrane stability at varying temperatures.  Plasma Membrane ◼Membrane carbohydrates – Glycoproteins and glycolipids—carbohydrate chains attached to proteins and lipids. – Identify the cell as “self” or “foreign” and act as receptors. Boundless.com. License: CC BY-SA: Attribution- ShareAlike Plasma Membrane ◼Membrane proteins – Receptor proteins Bind and respond to ligands (ions, hormones) – Carrier proteins Transport specific solutes through membrane – Channels Regulate water flow and solutes passing through membrane Gated channels open or close to regulate passage of substances  Official (Closed) - Non Sensitive The Nucleus. The nucleus holds the genetic material to direct Contents of the nucleus all the functions in the body. Nucleolus Nuclear organelles Synthesize rRNA and assemble ribosomal subunits Made of RNA, enzymes, and histones DNA coiled around proteins called histone 57  Official (Closed) - Non Sensitive Nucleus Sister chromatids* Centromere* DNA coiled around Supercoiled proteins called histone region Cell prepared for division Visible chromosome Loosely coiled into chromatin in non- dividing cells Nondividing cell Chromatin in Tightly coiled nucleus chromosomes DNA form before double division helix Nucleosome Histones  Official (Closed) - Non Sensitive Most of the cell cycle is spent in interphase. Organelles carry on their usual functions. Interphase The cell gets ready to divide. It grows larger, the Cell cycle number of organelles doubles, and the DNA replicates. Divided into three main stages: G1, S, G2. Cell division Replication of cell  Official (Closed) - Non Sensitive Cell cycle: Interphase Phases of interphase: G1 stage—the cell performs its normal function. Also doubles its organelles and accumulates the materials needed for DNA synthesis. S stage—DNA replication. After the S stage, each chromosome consists of two identical sister chromatids. G2 stage—synthesizes the proteins needed for cell division.  Official (Closed) - Non Sensitive Control of cell cycle The cell cycle is controlled by checkpoints, which delay it until certain conditions are met. The cell cycle may also be controlled by external factors, such as hormones and growth factors. Failure of the cell cycle control mechanisms may result in unrestricted cell growth, or cancer. Official (Closed) - Non Sensitive Loss of Normal Growth Control Normal cell division Cell Suicide or Apoptosis Cell damage— no repair Cancer cell division First Second Third Fourth or mutation mutation mutation later mutation Source: National Cancer Institute, Uncontrolled growth USA Official (Closed) - Non Sensitive Cancer Cells Source: National Cancer Institute, USA In hyperplasia, there is an In dysplasia, the cells look increase in the abnormal under a number of cells microscope but are not in an organ or cancer. Hyperplasia and tissue that dysplasia may or may not appear normal become cancer. under a microscope. Official (Closed) - Non Sensitive Genes, if mutated, that can result in tumors or cancers 1. Proto-oncogene The genes that code for the positive cell cycle regulators are called proto- oncogenes. Proto-oncogenes are normal genes that, when mutated in certain ways, become oncogenes, genes that cause a cell to become cancerous. 2. Tumour suppressor gene Tumor suppressor genes are segments of DNA that code for negative regulator proteins, the type of regulators that, when activated, can prevent the cell from undergoing uncontrolled division. Official (Closed) - Non Sensitive Changes in Chromosome Number Monosomy—one type of chromosome Trisomy—one type of chromosome is is present in a single copy (2n − 1). present in three copies (2n + 1). Official (Closed) - Non Sensitive Changes in Chromosome Number An abnormal number of autosomes causes a developmental abnormality. Monosomy of all but the X chromosome is fatal. Trisomy is usually fatal, though there are some exceptions. Among autosomal trisomies, only trisomy 21 (Down syndrome) has a chance of survival after birth.  Official (Closed) - Non Sensitive Down Syndrome: trisomy 21) Most common autosomal trisomy. Three copies of chromosome 21. A woman over 40 is more likely to have a Down syndrome child. Characteristics: short stature; eyelid fold; flat face; stubby fingers; a wide gap between the first and second toes; a large, fissured tongue; a round head; a palm crease (simian line); intellectual disability.  Official (Closed) - Non Sensitive Turner Syndrome Are female; has only one X chromosome. Are short, with a broad chest. The ovaries, uterine tubes, and uterus are very small and underdeveloped; they do not undergo puberty or menstruate, and their breasts do not develop. Normal intelligence and can lead fairly normal lives if they receive hormone supplements. Official (Closed) - Non Sensitive Klinefelter Syndrome: (47, XXY) Are male, with two X chromosomes and one Y chromosome. The symptoms (speech and language delays) are often subtle; only 25% are diagnosed. All require assisted reproduction to father children. Receive testosterone supplements beginning at puberty.