BHSC 1200 Exam Review: Cells, Tissues and Organ Systems in Homeostasis

Terms in this set (35)

1. Describe anatomical position and the paired terms proximal/distal and medial/lateral.Standing upright, facing forward, arms at the sides, palms forward. Proximal/distal: closer to or farther from where a limb attaches. Medial/lateral: toward or away from the body's midline.
2. Sagittal vs frontal (coronal) vs transverse planesSagittal divides the body into left and right parts. Frontal (coronal) divides it into front (anterior) and back (posterior). Transverse divides it into upper (superior) and lower (inferior) parts.
3. What are the three components of a negative feedback loop? Give an example.A receptor detects a change, a control centre compares it to the set point, and an effector reverses the change. Example: when body temperature rises, the hypothalamus triggers sweating and skin vasodilation.
4. Give two examples of positive feedback in the body.Childbirth (stretching of the cervix triggers more oxytocin and stronger contractions) and blood clotting (activated platelets recruit more platelets). Positive feedback amplifies a change until an endpoint is reached.
5. What are the four primary tissue types?Epithelial (covers surfaces and lines cavities), connective (supports and binds, includes bone and blood), muscle (contracts) and nervous (conducts signals).
6. Where is simple squamous epithelium found, and why does it suit those sites?In the air sacs of the lungs (alveoli) and the lining of capillaries. A single thin layer of flat cells allows rapid diffusion of gases and nutrients.
7. Functions of the mitochondria, ribosomes, rough ER, Golgi and lysosomesMitochondria make most ATP. Ribosomes build proteins. Rough ER folds and processes proteins. Golgi modifies, sorts and packages them. Lysosomes digest worn-out parts and debris with enzymes.
8. Mitosis vs meiosisMitosis makes two genetically identical diploid cells for growth and repair. Meiosis makes four genetically different haploid gametes, with two divisions and crossing over.
9. What happens in the stratum basale, and what do melanocytes do?The stratum basale is the deepest layer of the epidermis, where cells divide to replace those shed at the surface. Melanocytes there make melanin, which absorbs UV light and protects cell DNA.
10. Osteoblasts vs osteoclasts vs osteocytesOsteoblasts build new bone matrix. Osteoclasts break down bone, releasing calcium. Osteocytes are mature bone cells trapped in the matrix that maintain it.
11. How do PTH and calcitonin regulate blood calcium?Parathyroid hormone raises blood Ca2+ by stimulating osteoclasts, increasing kidney reabsorption and activating vitamin D. Calcitonin from the thyroid lowers blood Ca2+ by inhibiting osteoclasts.
12. Axial vs appendicular skeletonAxial: skull, vertebral column, ribs and sternum, which protect and support the body's core. Appendicular: the limbs plus the pectoral and pelvic girdles that attach them.
13. Summarize the sliding filament mechanism of skeletal muscle contraction.Ca2+ released from the sarcoplasmic reticulum binds troponin, which moves tropomyosin off actin's binding sites. Myosin heads bind actin and pull (power stroke); ATP binding releases the myosin head so the cycle repeats.
14. Central vs peripheral nervous system, and somatic vs autonomicCNS: brain and spinal cord. PNS: all nerves outside it. Somatic: voluntary control of skeletal muscle. Autonomic: involuntary control of heart, smooth muscle and glands.
15. Sympathetic vs parasympathetic effectsSympathetic (fight or flight): faster heart rate, dilated pupils and airways, slower digestion. Parasympathetic (rest and digest): slower heart rate, constricted pupils, increased digestion.
16. List the parts of a reflex arc in order.Receptor, sensory (afferent) neuron, integration centre in the CNS (often an interneuron), motor (efferent) neuron, effector (muscle or gland).
17. Steroid hormones vs peptide hormonesSteroids (e.g., cortisol, estrogen) are lipid-soluble, cross the membrane and bind receptors inside the cell to change gene expression. Peptides (e.g., insulin) bind surface receptors and act through second messengers.
18. Insulin vs glucagonBoth come from the pancreatic islets. Insulin (beta cells) lowers blood glucose by promoting uptake and storage as glycogen. Glucagon (alpha cells) raises blood glucose by breaking down glycogen.
19. Trace blood flow through the heart starting at the venae cavae.Venae cavae → right atrium → tricuspid valve → right ventricle → pulmonary valve → pulmonary arteries → lungs → pulmonary veins → left atrium → mitral valve → left ventricle → aortic valve → aorta.
20. Order of the cardiac conduction systemSA node (pacemaker) → AV node (brief delay so the ventricles can fill) → bundle of His → right and left bundle branches → Purkinje fibres.
21. What do the P wave, QRS complex and T wave of an ECG represent?P wave: atrial depolarization. QRS complex: ventricular depolarization (atrial repolarization is hidden within it). T wave: ventricular repolarization.
22. Calculate cardiac output when heart rate is 70 beats/min and stroke volume is 70 mL.Cardiac output = HR × SV = 70 × 70 mL = 4900 mL/min, or about 4.9 L/min.
23. Main formed elements of blood and their functionsRed blood cells carry O2 bound to hemoglobin. White blood cells defend against infection. Platelets (cell fragments) help form clots.
24. Innate vs adaptive immunityInnate immunity is fast and non-specific (skin, inflammation, phagocytes). Adaptive immunity is slower at first but specific and has memory: B cells make antibodies, and T cells kill infected cells or coordinate the response.
25. What are the cardinal signs of inflammation?Redness, heat, swelling and pain, sometimes with loss of function. Vasodilation and leaky capillaries bring more blood, fluid and white blood cells to the injured area.
26. Name three functions of the lymphatic system.Returns excess tissue fluid to the blood, absorbs dietary fats from the small intestine (through lacteals), and filters lymph through lymph nodes as part of immune defence.
27. Explain inspiration using Boyle's law.The diaphragm and external intercostals contract, increasing thoracic volume. As volume rises, pressure in the lungs falls below atmospheric pressure, so air flows in.
28. How is most CO2 carried in the blood?About 70% travels as bicarbonate (HCO3−) in plasma, formed in red blood cells by carbonic anhydrase. The rest is bound to hemoglobin or dissolved.
29. What is the main chemical stimulus driving breathing rate?Rising CO2 (and the falling pH it causes), detected mainly by central chemoreceptors in the medulla. Low O2 becomes a strong stimulus only when it falls a lot.
30. Match each digestive enzyme or secretion to its target: salivary amylase, pepsin, pancreatic lipase, bile.Salivary amylase: starch. Pepsin (stomach): proteins. Pancreatic lipase: fats (triglycerides). Bile (liver, stored in the gallbladder) has no enzymes; it emulsifies fats.
31. Why is the small intestine so effective at absorption?Circular folds, villi and microvilli give it a huge surface area, and it is long. Most nutrient absorption occurs there.
32. What happens at each part of the nephron?Glomerulus: filtration of plasma. Proximal tubule: reabsorbs most water, glucose and salts. Loop of Henle: concentrates the medulla. Distal tubule and collecting duct: hormone-controlled fine-tuning.
33. ADH vs aldosteroneADH (from the posterior pituitary) makes the collecting ducts more permeable to water, giving concentrated urine. Aldosterone (adrenal cortex) increases Na+ reabsorption and K+ secretion; water follows the sodium.
34. Outline the renin-angiotensin-aldosterone system.Low blood pressure leads the kidneys to release renin, which leads to angiotensin II. Angiotensin II constricts blood vessels and triggers aldosterone release and thirst, raising blood volume and pressure.
35. Which hormone surge triggers ovulation?A mid-cycle surge of luteinizing hormone (LH) from the anterior pituitary, triggered by rising estrogen.