Difficulty: Intermediate | Prerequisites: Chapter 2 Part 1 notes (nervous and endocrine systems).
This covers the remaining body systems that health psychologists need to understand: cardiovascular, respiratory, digestive, renal, reproductive, genetics and immune. Each system is relevant because psychological and social factors can influence how it functions and breaks down. The immune system section is particularly important for later chapters on stress and illness.
The cardiovascular system transports oxygen, nutrients and waste via the blood. The respiratory system exchanges gases and is controlled by the medulla. The digestive system breaks food down mechanically and chemically. The renal system filters waste. The reproductive system is regulated by hormones and vulnerable to STDs. The immune system defends against pathogens using both nonspecific (natural) and specific (humoral and cell-mediated) mechanisms, and autoimmunity is what happens when it attacks the body's own tissue.
Cardiovascular system
The heart, blood vessels and blood. The body's transport system for oxygen, nutrients, waste, hormones and heat.
Cardiac cycle
One complete sequence of heart contraction (systole) and relaxation (diastole).
Systole
The contraction phase: blood is pumped out of the heart and blood pressure in the vessels increases.
Diastole
The relaxation phase: heart muscles relax, blood pressure drops and blood flows back into the heart.
Blood pressure
The force blood exerts against vessel walls. Highest during systole, lowest during diastole.
Atherosclerosis
A major cause of heart disease in which fatty deposits (plaque) build up inside artery walls, narrowing them.
Angina pectoris
Chest pain caused by insufficient oxygen supply to the heart or inadequate removal of CO2 and waste products. Think of it as the warning sign that the heart is not getting enough blood.
Myocardial infarction (heart attack)
Occurs when a clot develops in a coronary vessel and blocks blood flow to the heart muscle.
Plasma
The fluid portion of blood, making up about 55%. Contains plasma proteins, electrolytes and substances being transported.
Asthma
A severe allergic reaction causing bronchial spasms, inflammation, mucus production and reduced oxygen supply. Can be triggered by allergens, emotional stress or exercise.
Bolus
The soft, rounded lump of chewed food lubricated by saliva that passes through the oesophagus.
Peristalsis
Unidirectional muscular movement that pushes food through the digestive tract toward the stomach.
Duodenum
The intersection of the stomach and lower intestine where pancreatic juices and bile enter to continue digestion.
Gastroenteritis
Inflammation of the stomach and small intestine lining, typically from contaminated food or drink. Symptoms (vomiting, diarrhoea, cramps, nausea) appear 2-4 hours after ingestion.
Peptic ulcer
An open sore in the lining of the stomach or duodenum, resulting from hypersecretion of hydrochloric acid and the action of pepsin. The bacterium Helicobacter pylori contributes to many ulcers.
Appendicitis
Inflammation of the appendix caused by accumulation of waste and bacteria. If the appendix ruptures, bacteria released into the abdominal cavity can cause peritonitis.
Renal system
Kidneys, ureters, urinary bladder and urethra. Regulates bodily fluids; principal function is to produce urine.
Estrogen
Hormone produced by the ovaries that drives the development of secondary sex characteristics in females.
Progesterone
Hormone produced during the second half of the menstrual cycle to prepare the body for pregnancy.
Endometriosis
A condition where endometrial lining tissue migrates to fallopian tubes or the abdominal cavity and grows there.
Amenorrhea
Absence of menstruation.
Phagocytosis
The process by which white blood cells (phagocytes) ingest and destroy microbes. Phagocytes are overproduced during infection so large numbers can be sent to the site.
Humoral immunity
Defence against extracellular pathogens mediated by B lymphocytes, which produce and secrete antibodies.
Cell-mediated immunity
Defence against intracellular pathogens mediated by T lymphocytes from the thymus gland, which kill infected cells directly.
Autoimmunity
When the body fails to recognise its own tissue and attacks it with antibodies. Examples include type 1 diabetes, rheumatoid arthritis, inflammatory bowel disease and lupus.
Natural killer (NK) cells
Immune cells that recognise nonself material and destroy it by releasing toxic substances. Part of the natural (nonspecific) immune response.
Cytokines
Proteins released by macrophages that lead to inflammation, fever and wound healing.
The cardiovascular system (heart, blood vessels, blood) is the body's transport network. Blood carries oxygen from lungs to tissues, CO2 from tissues to lungs, nutrients from the digestive tract to cells, waste to the kidneys, hormones to target organs and heat to the skin surface.
Cardiac cycle: contraction (systole) + relaxation (diastole)
Systole: blood pumped out of heart, blood pressure increases
Diastole: muscles relax, blood pressure drops, blood returns to heart
Atherosclerosis: fatty plaque narrows arteries; a major cause of heart disease
Angina pectoris: chest pain from insufficient oxygen to the heart
Myocardial infarction: a clot in a coronary vessel blocks blood flow to the heart (heart attack)
Blood itself contains roughly 55% plasma (fluid portion with proteins, electrolytes and transported substances) and 45% cells. An adult body holds about 5 litres.
Respiratory movements are controlled by the respiratory centre in the medulla. When blood CO2 levels rise too high, respiration increases to expel it.
Asthma: a severe allergic reaction triggered by allergens (dust, dander, pollens, fungi), emotional stress or exercise. Muscles surrounding the air tubes constrict, the lining inflames and swells, mucus clogs the bronchioles, oxygen supply drops and CO2 increases.
Common cold: viral infection with a 12-72 hour incubation period. Secondary bacterial infections may follow because the virus inflames mucous membranes and weakens their barrier function.
Lung cancer: symptoms include shortness of breath, coughing (sometimes blood) and weight loss. Primary cause is smoking. 238,340 new cases in the US in 2023.
Food is lubricated by saliva into a bolus, pushed through the oesophagus by peristalsis and enters the stomach. The stomach produces pepsin and hydrochloric acid. Even the sight or thought of food triggers gastric juices.
Food then progresses to the duodenum where pancreatic juices (enzymes for proteins, carbs and fats), insulin (for glucose entry into tissues) and bile (from the liver, stored in the gallbladder, breaks down fats) continue digestion.
Gastroenteritis: inflammation of stomach and small intestine lining from contaminated food, excessive eating/drinking or food poisoning. Symptoms (vomiting, diarrhoea, cramps, nausea) appear 2-4 hours after ingestion.
Diarrhoea: intestinal lining cannot properly absorb water or digested food, causing fluid and electrolyte imbalance.
Dysentery: diarrhoea with mucus, pus and blood. Caused by protozoan (amoebic) or bacterial organisms attacking the large intestine.
Peptic ulcer: open sore in stomach or duodenal lining from hypersecretion of hydrochloric acid and pepsin digesting the stomach wall. Helicobacter pylori bacteria contribute to many ulcers.
Appendicitis: waste and bacteria accumulate in the appendix. If the opening is obstructed, bacteria proliferate. A ruptured appendix releases bacteria into the abdominal cavity (peritonitis), which can be fatal.
Kidneys, ureters, urinary bladder and urethra. The kidneys regulate bodily fluids and produce urine. Ureters move urine to the bladder via peristaltic waves. Most common disorders are urinary tract infections, which are more prevalent in women.
Females have two ovaries in the pelvis. Each month one ovary releases an ovum into the fallopian tubes. If not fertilised, the ovum remains in the uterine cavity for 14 days and is then flushed out during menstruation along with the endometrium.
The ovaries produce estrogen (secondary sex characteristics) and progesterone (prepares body for pregnancy during the second half of the menstrual cycle).
Disorders: STDs (herpes, gonorrhoea, syphilis, genital warts, chlamydia, AIDS), chronic pelvic inflammatory disease, vaginitis, endometriosis (endometrial tissue migrating outside the uterus), cysts, fibroids, amenorrhea (absent menstruation) and oligomenorrhoea (infrequent menstruation).
Genetic information lies in 46 chromosomes per cell (23 from each parent). Two of the 46 are sex chromosomes: X from the mother and either X (female) or Y (male) from the father. Genetics regulates physical traits and behavioural factors.
Disease enters the body through indirect, biological or mechanical transmission (e.g. dirty hands, contaminated water). Once a microbe reaches the body, it penetrates tissue through the skin, respiratory tract, digestive tract or genitourinary system. Virulence depends on aggressiveness (resisting the body's defences) and toxigenicity (producing poisons).
Immunity develops naturally (breastfeeding, acquired disease) or artificially (vaccination).
Nonspecific immune mechanisms: general responses to any infection. Key cells include granulocytes (neutrophils that ingest pathogens), macrophages (release cytokines causing inflammation and fever), and natural killer cells (destroy nonself material with toxic substances).
Specific immune mechanisms: acquired after birth, targeting particular pathogens.
Humoral immunity: B lymphocytes produce antibodies against extracellular pathogens (bacteria, bacterial toxins, viral reinfection)
Cell-mediated immunity: T lymphocytes from the thymus target intracellular pathogens by killing infected cells directly
Phagocytosis: phagocytes ingest microbes and are overproduced during infection. Antimicrobial substances like interferon, hydrochloric acid and lysozyme also help.
Autoimmunity: the body mistakes its own tissue for a foreign invader and produces antibodies to attack it. Conditions include type 1 diabetes, rheumatoid arthritis, inflammatory bowel disease and lupus.
Students confuse humoral and cell-mediated immunity. Humoral = B lymphocytes making antibodies against extracellular threats (bacteria). Cell-mediated = T lymphocytes killing infected cells from within (intracellular pathogens).
Students think autoimmunity is the same as immunodeficiency. Autoimmunity is the immune system attacking the body's own tissue. Immunodeficiency is the immune system being too weak to fight external threats.
Students assume peptic ulcers are caused only by stress. While stress is a contributing factor, hypersecretion of hydrochloric acid and, in many cases, Helicobacter pylori infection are the primary causes.
Students mix up systole and diastole. Systole = contraction, pressure UP. Diastole = relaxation, pressure DOWN.
⚠️ Know the difference between humoral immunity (B cells, antibodies, extracellular) and cell-mediated immunity (T cells, direct killing, intracellular).
⚠️ Systole vs. diastole: which raises blood pressure and which lowers it.
⚠️ Be able to explain autoimmunity and name at least two autoimmune diseases.
⚠️ Know the role of Helicobacter pylori in peptic ulcers.
⚠️ Asthma triggers (allergens, stress, exercise) and the mechanism (bronchial spasms, inflammation, mucus) are commonly tested.
⚠️ Natural immunity cells (granulocytes/neutrophils, macrophages, NK cells) and what each does.
True or False: Diastole is when blood pressure is at its highest.
False. Blood pressure is highest during systole.
Fill in the blank: ______ immunity involves B lymphocytes producing antibodies.
Humoral.
True or False: Autoimmunity means the immune system is too weak to fight pathogens.
False. Autoimmunity is the immune system attacking the body's own tissue.
Fill in the blank: The bacterium ______ contributes to the development of many peptic ulcers.
Helicobacter pylori.
True or False: Natural killer cells are part of the specific immune response.
False. They are part of the natural (nonspecific) immune response.
Q: Describe the mechanism of an asthma attack.
A: An allergen (or emotional stress/exercise) triggers bronchial spasms. Muscles surrounding the air tubes constrict, the lining of the air tubes inflames and swells, and mucus is produced that clogs the bronchioles. This obstructs airflow, reduces oxygen supply and increases carbon dioxide in the blood.
Q: What is the difference between humoral and cell-mediated immunity?
A: Humoral immunity is mediated by B lymphocytes that produce antibodies against extracellular pathogens (bacteria, toxins, viral reinfection). Cell-mediated immunity is mediated by T lymphocytes from the thymus gland that kill intracellular pathogens by attacking infected cells directly.
Q: Explain what happens during a myocardial infarction.
A: A blood clot develops in a coronary vessel and blocks the flow of blood to the heart muscle. The affected portion of heart tissue is deprived of oxygen and nutrients, which can cause permanent damage or death of that tissue.
Q: What is autoimmunity? Give two examples.
A: Autoimmunity occurs when the body fails to recognise its own tissue and produces antibodies to attack it. Examples include type 1 diabetes, rheumatoid arthritis, inflammatory bowel disease and lupus.
Q: Trace the path of food through the digestive system from mouth to duodenum.
A: Saliva lubricates food into a bolus. The bolus passes through the oesophagus via peristalsis into the stomach, where gastric secretions (pepsin and hydrochloric acid) break it down further. Food then progresses to the duodenum, where pancreatic juices (protein, carb and fat enzymes), insulin and bile (from the liver, stored in the gallbladder) continue digestion.
The cardiovascular system connects to later chapters on stress and coronary heart disease: chronic sympathetic activation (Chapter 2 Part 1) contributes to atherosclerosis and hypertension. The immune system is central to psychoneuroimmunology, where stress hormones (corticosteroids) suppress immune function. The digestive system disorders here reappear when discussing psychosomatic conditions and the role of stress in ulcers.
cardiovascular system, heart, cardiac cycle, systole, diastole, blood pressure, atherosclerosis, angina pectoris, myocardial infarction, heart attack, plasma, respiratory system, asthma, lung cancer, smoking, common cold, viral infection, digestive system, bolus, peristalsis, pepsin, hydrochloric acid, duodenum, pancreas, insulin, bile, gallbladder, gastroenteritis, diarrhoea, dysentery, peptic ulcer, Helicobacter pylori, appendicitis, peritonitis, renal system, kidneys, UTI, reproductive system, ovaries, estrogen, progesterone, menstruation, STDs, endometriosis, amenorrhea, genetics, chromosomes, sex chromosomes, immune system, phagocytosis, phagocytes, humoral immunity, B lymphocytes, cell-mediated immunity, T lymphocytes, autoimmunity, natural killer cells, cytokines, granulocytes, neutrophils, macrophages, PSY320 Chapter 2