Final Flashcards
What do hormones do in the body?
They modulate:
- Growth and development
- Homeostasis
- Reproduction
- And other things in the physiome including aspects of the CCN
They have similar chemical structures with specific receptors
Growth and Development Hormone
Growth Hormone
- Hypothalamus
- Sends message to the Anterior Pituitary Gland
- Send GH to Liver, Bone, Skeletal Muscle
Reproduction Hormone
Oxytocin
- Hypothalamus (Suckling by infant)
- Sends message to Posterior Pituitary Gland
- Sends OT through bloodstream to Breast
Homeostasis Hormones
Blood Calcium - Thyroid gland - Calcitonin to decrease - Parathyroid Hormone to increase Blood Glucose - Pancreas - Insulin to decrease - Glucagon to increase
Where do hormones come from?
Endocrine glands - Adrenal gland
Organs that produce them as a secondary function - kidneys
How does the nervous system interact with the endocrine system to form the foundation of the CCN (from organ to the person level)?
- Some nerves release hormones directly into the bloodstream (neurohormones)
- All primary endocrine glands and secondary endocrine tissue are innervated by neurons of the autonomic nervous system. Nerve signals, via local neurotransmitter release, can modulate hormone secretion.
- Neurons in the CNS and PNS - along with astrocytes in the CNS and astrocyte-like cells in the PNS - have receptors for many hormones (insulin (hydrophilic) and estrogen (lipophilic))
Hormones of the Pituitary Gland
Neuro Endocrine
Posterior Pituitary Gland - Oxytocin
Anterior Pituitary Gland - Growth Hormone
Multi-organ hormone axis
Tropic Hormones - between Hypothalamus and Pituitary
GH goes to Liver and other cells for growth
Adrenal cortex releases cortisol for stress response
Thyroid gland releases thyroid hormone for metabolic rate
Gonads release sex hormones for reproduction
Hormones of the Pancreas
Has endocrine and exocrine function
Diseases of Pancreas
Pancreatitis
Pancreatic Cancer
Pancreas - Single Organ Hormone Axis
- Excretory cells on the outside (digestion enzymes)
- Islets within
- Alpha cells: glucagon
- Beta cells: insulin
Type I Diabetes
Autoimmune disease where beta cells die
Type II Diabetes
Beta cells no longer work efficiently or properly due to overworking hormonal cells
Prohibited Doping Drugs
Growth hormones
Why are anabolic steroids toxic?
- The effective dose is too high
2. The dose is not timed to mimic natural hormone production (hormones are released according to complex rhythms)
Nonspecific defenses
Innate Immune System (always there)
- First line of defence with nonspecific physical and chemical surface barriers
- Second line of defence with nonspecific internal cellular and chemical defence
Specific defenses
Adaptive Immune System (can gear up or down)
First line of Defence
- Epithelial barriers (skin)
- Washing away (tears, saliva, bladder, respiratory tract)
Second line of Defence
- Defensive cells
- Defensive proteins
- Inflammation
- Fever
Inflammation
Blood vessels widen
- Redness from blood flow carrying defensive cells
- Heat from increased metabolic rate to speed heal
Capillaries become more permeable
- Swelling from fluids seeping in
- Pain to hamper movement to allow for healing
Lysis by Complement
Protein-based defence
- Proteins form hole in cell wall
- Water enters the cell
- Bacterium bursts
- Complement system also has over 50 proteins produced by liver
Destruction by Phagocytosis
Cell-based defence
- Engulfs bacterium
- Fuses with lysosomes
- Breakdown with enzymes and released
Fever
Driving our core body temperature higher to prevent pathogens from reproducing efficiently
What is the local support and defence system?
- Maintenance and Support
- Adaptation and Repair
- Resident Defence
- Migrant Defence
Parenchymal Cells
- Most prominent cell type in terms of function and sometimes mass
- The critical functional portion of the gland or organ
Non-parenchymal cells
Basic Logic Unit of LSDS
- Nerve endings
- Capillary endothelial cells
- Support and defence cells of lymphoid origin
- Support and defence cells of myeloid origin
- Fibroblast
- Stem cells
Pancreas and the LSDS
- Exocrine secretions exit into duodenum (digestive enzymes
- Endocrine secretions go into blood (insulin, glucagon)
Diseases of the Pancreas
- Pancreatitis
- Diabetes
- Exocrine Pancreas Insufficiency
- Cystic Fibrosis
- Pancreatic Cancer
- Pancreatic Steatosis
Composition of Blood
- 55% Plasma: medium for transporting materials
- 45% Formed elements: red blood cells, white blood cells, platelets
- Transport oxygen, defend against diseases, blood clot
Production and Movement of Cells in Blood
- Monocytes become macrophages
- B-cells, T-cells, NK-cells, NKT-cells, come from lymphocytes
Cells in Blood Migration
- White blood cells migrate into and out from peripheral tissues
- Red blood cells and platelets stay in capillary tubes
Cell Markers
- Self MHC marker labels as friend to support
- Antigen on pathogen is recognized as foe to attack
Phagocytosis
- Invader enters the body
- Macrophage engulfs and digests invader, and places antigen on its surface
- Presents it to helper T cell and secretes cytokine to activate helper T
B-cell Response
Antibody-mediated response
- Activates naive B cell
- Cell divides and differentiates into Effector Cytotoxic B-cell
- Secretes antibodies which are proteins which bind to antigens on pathogens or toxins outside of cells
T-cell Response
Cell-based immunity route of attack
- Activates naive cytotoxic T-cell
- Cell divides and differentiates into Effector Cyctotoxic T-cell
- Kills cells infected with intracellular pathogens by a variety of mechanisms
What is left after fighting an illness?
- In tissue, bone marrow, and thymus
- Memory in the form of Memory Helper T Cells, Memory Cytotoxic T cells, and Memory B cells populations
- Also in the CNS
Function of Memory in T and B cells
Faster and bigger immune response upon second exposure to antigen
Homeostatic Elements of Adaptive Immune Response
Treg cell: Regulatory T-cell or Suppressor T-cell
Components of Cardiovascular-Lymphatic System
- Fluids
- Blood
- Lymph
- Cerebrospinal fluid
- extracellular fluid - Vessels
- blood vessels
- lymph vessels
- cerebrospinal fluid fluids - Organs
- Heart
- Kidney
- Spleem, thymus, tonsils
- Lymph nodes - Innervation
- Sympathetic
- Parasympathetic
- Sensory - Stem Cell Pool
- Bone Marrow
Diseases of the fluids of the circulatory system
- Anemia (iron deficiency or hemolytic)
- Coagulation disorders - platelet/clotting factors
- Leukemias
- White blood cell deficiencies - immuno deficiences
- Dehydration/hemoconcentration
- Blood loss
Coagulation Disorder: Platelet Dysfunction
- Platelets: small fragments of cells that look for trouble and clot
- Detect pathology or breach in blood vessel and a platelet aggregation
- Aspirin inhibits this - long term use may lead to bleeding issues
Coagulation Disorder: Fibrin Network Dysfunction
- Clotting factors released, inactive protein into prothrombin activator, prothrombin into thrombin, fibrinogen into fibrin, blood clot
- Liver produces proteins of clotting and complement cascade
- Genetic disorders affect one of these proteins
- Blood thinners like warfarin
White Blood Cell Deficiencies
- X-SCID: decreased white blood cells
- HIV AIDS: Decreased T-helper cells (only unique disease may be Kaposi’s Sarcoma (cancer))
Blood Vessels
- Capillaries: 1 cell layer that is porous
- Arteries: more smooth muscle
- Veins: lower pressure
Blood Flow Circuit
- 2 main loops (providing oxygen for cellular respiration and environmental interface with lungs)
- Continuous loops in parallel
- Most blood is held in veins
Lymphatic System
- collect material from extracellular fluid at capillary beds and form lymph
- capillaries have blunt closed ends
- Move lymph to the major veins of the blood system
- not a continuous loop
- Cerebrospinal fluid drains back into CNS circulation and lymphatic system at various point outside the brain
Lymphatic Vessels
- Capillary: flaps produce openings larger than blood capillaries
- Many valves throughout
Division of Labor in Tissue
- Arterioles: main site of blood flow and blood pressure regulation
- Capillaries: nutrient, waste, fluid exchange at local level
- Venules: main site of lymphocytes crossing from blood to lymph nodes
Blood vessels velocity and surface area
- High velocity and small surface area = direct, rapid conductance of blood
- Low velocity and large surface area - optimal exchange
Organ-specific control of blood flow
- Resting blood flow: evenly spread with highest in GI tract
- Exercise blood flow: higher in skeletal muscle
- Cardiac output also varies
- Can also depend on after a big feast or during an exam
Blood movement in Veins
- Valves prevent backflow
- Contraction of skeletal muscles squeeze vein
- Breathing causes pressure changes that moves venous blood towards heart
Diseases of circulatory system
- Arteries: aneurysms, atherosclerosis
- Veins: varicose veins, deep vein thrombosis
- Lymphatic vessels: lymphedema
- Cerebrospinal fluid: hydrocephalus
Cerebral aneurysm
- Weakened arterial wall in brain causing a bulge
- Can lead to burst vessel or blood clot
Atherosclerosis
- Narrowing of artery lumen due to plaque obstruction or blood clot
- Stars with pre-teens in Canada
Hydrocephalus
- excess accumulation of fluid in brain
- excess cerebrospinal fluid production can occur in elderly
- increased pressure
Swelling of vessels
- Deep vein thrombosis: blood clot formation in deep vein, often not visible with weird feeling/pain
- Varicose veins: veins that have become enlarged and twisted
- Lymphedema: compromised lymph system causing fluid build-up (later stages of diabetes)
- All three have increased risk with age
Circulatory System Organ Functions
- Heart: pumps blood
- Kidneys: filter and adjust volume and content of blood plasma, indirectly control blood pressure
- Spleen: filter and remove old read cells and platelets, site of maturation of white blood cells
- Thymus: site of maturation of white blood cells, major site of antigen presentation and memory formation in B cell populations
- Tonsils: site of storage and maturation of white blood cells
Heart as a Muscular Pump
- Made of cardiac muscle tissue called myocardium
- Neural input: involuntary, autonomic
- Neural conduction: gap junctions that are very fast, contract as a unit (syncytium)
- Metabolism: very high oxidative capacity (lots of mitochondria) so fatigue resistant
Structure of Heart
- 4 chambers: 2 atria and 2 ventricles
- Right side (pulmonary circuit): contains blood rich in CO2, returns from the tissues and flows out to the lungs
- Left side (systemic circuit): contains oxygen rich blood, returns from lungs and flows to tissues
Heart Valves
- “Lub”: enter atria with atrioventricular valves (mitral) closing
- “Dub”: leave ventricles with semilunar valves (aortic) closing
Heart Valve Issues
- Stenosis: narrowing of a valve. May be congenital, due to calcification, or scarring from rheumatic fever. Can cause fatigue, shortness of breath, exercise intolerance, heart failure, fluid buildup in lungs, and death
- Occurs in aortic valve (left semilunar valve) and mitral valve (left AV valve)
Artificial Heart Valves
Non-biological valves:
- Durability: supposed to last 20+ years
- Clot formation: requires consistent anticoagulant therapy (blood thinning drugs)
- Getting stuck
- Resistance to flow: vulnerability to backflow and regurgitation
Biological Valves (usually porcupine or pig):
- Referred to as xenotransplantation (between species): requires immunosuppression therapy
Cardiac Cycle
- Atrial Systole: both atria contract to force blood into ventricles
- Ventricular Systole: both ventricle contract forcing blood into pulmonary trunk and aorta
- Early Diastole: Atria and ventricles are relaxed and fill passively
- Later Diastole: Ventricles are still relaxing and filling passively
Enlargement of the Heart
Hypertrophy: a sign of being “overworked”
- Bad: causes include high blood pressure and narrowing of aortic valve which the heart has to work harder against
- Good: Athletes heart - occurs in both endurance athletes and weightlifters
Electrical Aspects of the Heart
- SA node initiation
- Atria contract and signal reaches AV node
- Signal conducted to Purkinje fibers through Bundle of His
- Ventricles contract
- Miscommunication causes “arrhythmias”, such as tachycardia and bradycardia
- Many heart attacks end in “fibrillation”, when cells depolarize independently
Repairing Electrical Aspects of the Heart
Pacemakers:
- Can be disrupted by shocks, airport scanners, personal devices, MRI
- Allow for functioning at base level
Autonomic Nerve System Control of Heart Rate
- We can’t control it
- Impairments of spinal chord leads to paraplegia and quadriplegia
- Parasympathetic and sympathetic nerves can bring up or down a little
Hormonal Control of Heart Rate
- Rapidly bring it up with nothing to bring it down
- Adrenal gland (on top of kidneys) releases epinephrine and norepine into blood and heart (neurotransmitters)
Angioplasty
- Treating atherosclerosis
- Catheter and balloon threaded into coronary artery to the point of blockage
- Balloon is inserted into blocked area and inflated
- Plaque is pushed to artery walls and held there by stent
Bypass Surgery: Coronary Artery Bypass Graft (CABG)
- Vein from leg (saphenous vein) used for bypass in heart
- Creates a loop around the blockage
- When vein is put under high pressure adapts to become artery
Sometimes taken from brachial artery
Red Heart Pill (Cardio-Polypill)
- Low dose aspirin
- A statin drug
- 1/3 dose of 3 types of blood pressure lowering drugs
- Cheap drugs that would drastically increase life span
- Pharmacy wouldn’t make money and certain individuals will lose life span
Zeitgeber
- Cues from the environment as to how to synchronize activities of the system
- Primary one is light
- Second major one is eating/food consumption
Sphincters of the GI Tract
- 6 to segregate function in the tube and prevent lumen content backflow
- Controlled by second brain
- Upper and lower esophageal sphincter, pyloric sphincter, ileocecal valve, internal and external anal sphincter
- Only first and last under voluntary control
Basic Processes of GI Tract
- Motility (always downwards)
- Secretion
- Digestion
- Absorption
- Excretion
- Always working 24/7
General Structure of the GI Tube
- Second brain = enteric nervous system
- Intestinal epithelium: single cell layer separates the inside and outside of the body
- Multiple layers
- Smooth muscle not under voluntary control
GI Tract Properties
- 28 ft long
- Surface area of tennis court (200-400 square meters)
- Highly variant transit time: marker of 30-80 hours with 5-8 hours for normal passage through stomach and small intestine
- Senses and expels noxious substances
- Continuously interacts with gut microbiome
Diaphragm
- Separates thoracic cavity and abdominal/peritoneal cavity
- Abdominal breathing has better health benefits
Peristalsis
- in esophagus
- one-way
- multiple layers of smooth muscle with gap junctions and pacemaker cells
- also used in stomach and large intestine
Segmentation
- in small intestine
- movement in both direction for greater mixing
- multiple layers of smooth muscle with gap junctions and pacemaker cells
- also used stomach and large intestine
Diseases of Motility in GI Tract
- GERD (gastroesophageal reflux disease)
- Gastroparesis (pyloric sphincter)
- SBBOS (small bowel bacterial overgrowth syndrome): ileocecal valve with poor absorption of B12
- Chronic constipation
Secretion
- From glands into lumen: saliva from salivary glands, acid from gastric glands, bicarbonate from Brunner’s glands, pancreatic juice from exocrine pancreas, bile from liver
- From individual cells: mucus secretion from goblet cells, defensins from paneth cells, secretory IgA from epithelial cells
- secretion happening in every direction and in various sizes/types
Bulk Fluid Secretion and Fluid Flow
- helps maintain blood volume (2500 mL of plasma)
- about 2000 mL needed per day (depending on other factors)
- about 2000 mL of fluid loss per day
- help solubilize and digest food stuff
- urine and sweat output drives thirst
- can lead to headaches, mood, lethargic
Diseases of Secretion in GI Tract
- Cystic Fibrosis
- Inflammatory and secretory diarrhea
- Achlorhydria (low acid production or excessive use of antacid drugs)
- Xerostomia (dry mouth from lack of saliva)
Enteric Nervous System
- Second brain within the GI system
- 2 way communication between the brain and the second brain
- Part of both the short and long reflex pathway of control
Motivation to Eat
- Hedonic Hunger: for pleasure
- Homeostatic Hunger: for metabolism
- Usually a continuum
- Shifted more to hedonic
Nutritional Status
- Deficiency of nutrients and energy
- Adequacy
- Excess of
- Part of the obesogenic environment
Processing Food
- processed in 4-6 hours, but takes longer to absorb
- convert polymers and macromolecules into amino acids, monosaccharides, fatty acids, vitamins, minerals
- if deficient of an essential nutrient, we have nutritional deficiency disease
Cephalic Phase of Digestion and Absorption
- chemical and mechanical digestion begins in the mouth
- chewing: mastication
- salivary secretion is under autonomic control, which softens and lubricates food, and provides enzymes (amylase and some lipase)
- all senses involved in preparing to eat, as seen in brain imaging
Tongue
- has taste buds with no regional segregation of flavour
- sweet - sucrose
- sour - HCl
- salty - table salt
- bitter - quinine (medicine for malaria)
- savory/umami - L-theanine
- taste buds also found in small intestine
Gastric Phase of Digestion and Absorption
- Upper stomach: muscular stomach
- Lower stomach: gastro stomach
- Salivary hormones promote integrity of epithelium
- Alcohol and aspirin partly absorbed in stomach: can damage epithelium
Small Intestinal Phase of Digestion and Absorption
- bulk of process here
- Duodenum: short in length but high villi and number of microvilli to maximize absorption
- Jejunum
- Ileum: long in length but short villi and low number of microvilli
Accessory Organs of Small Intestine
- Liver: produces bile for gall bladder
- if duodenal epithelial cells sense fat they signal gallbladder to release bile
- Pancreas
- Exocrine: uses a duct
- Endocrine: ductless
Microvilli
- small intestinal mucosa: increase SA for absorption
- single cell epithelium
Secretions into Small Intestine
- Bicarbonate: from cells in epithelium and pancreas
- Digestive enzymes: from pancreas
- Bile acids: from liver/gallbladder
Digestive Enzymes anchored on epithelial cells
- Disaccharidases
- Amino peptidases
- to absorb chemical, must be soluble in water-liquid of lumen
Nutrient Absorption
- Polysaccharidases and disaccharidases to break down into monosaccharides
- Proteases and peptidases break down proteins into amino acids
- Lipases break down fats with help from bile salts
- Vitamins and minerals are simply absorbed
- Paracellular absorption (between cells) by actively controlled channels
Large Intestinal Phase of Digestion and Absorption
- Ileal chyme comes in from Ileum
- Includes unabsorbed nutrients, hormones/chemical messangers, soluble/insoluble fibre, microbes, cellular debris, excretion products from the liver (bile pigments)
- Highest microbial mass
What happens in the Large Intestine?
- Colonic epithelium absorbs water and simple ions
- Resident microbes digest and absorb prebiotics by fermentation and short-chain fatty acids
- Resident microbes produce some vitamins from their metabolism
- Resident microbes produce gases during digestion
- Newly arriving microbes (probiotic) seek to get a foothold in the ecosystem (cooperate and compete)
Gastric Bypass Surgery
- For morbid obesity
- Roux-en Y Procedure: small pouch created in upper stomach and attached to small intestine (bypassing most of stomach and duodenum)
- Lap Banding: silicone band with saline place around upper stomach under the skin and can be inflates (cheaper)
- 40-50% weight loss within a year
- Hormonal changes: increased PYY levels and decreased ghrelin levels (success of surgery may be partially due to appetite regulating hormonal change)
Energy Distribution System
- Food -> Digestion -> Small intestine -> Absorption -> Primary fuels in blood plasma
- Functional Primary Fuels: in all cell types
- Combustion and harvesting energy as ATP
- Precursor for biosynthetic pathways (non-storage)
- Stored Primary Fuels (in some cell types)
Macronutrients and their Storage
- Stored as glycogen in liver/skeletal muscle
- Stored as proteins in skeletal muscle
- Stored as triglycerides in adipose tissue
- No storage in extracellular space or fluid
Energy Storage
- Expend about 2000 kcal/day
- Most stored in our adipocytes (>15 kg): 50 day supply
- Carbohydrates: 1 day supply (only 30 g of glucose in blood)
- Proteins: 12 day supply (used in starvation)
- Fats and Proteins are functional stores: for insulation, cushioning, and skeletal muscle mass
Energy Distribution during Absorptive States
- Absorptive state (post-prandial): 3-6 hours following meal (0-4) where nutrients in bloodstream sustained from intestinal absorption
- Insulin is increased and excess is turned into storage
- Post-absorptive state: between meals where energy stores must be mobilized to supply minimum primary fuel loads in the blood plasma
- Glucagon is increased
- Cycle between two states
Energy Distribution System in Brain
- Primary fuels cross blood brain barrier under controlled conditions via brain capillary endothelial cell transporters
- Uses a large amount of glucose to form ATP (up to 25% of total body usage)
- Does not store any primary fuels at appreciable levels
- Astrocytes partially control nutrient flow to neurons, make glycogen as extra reservoir of fuel for local control of glucose, and make ketone bodies and lactate as secondary fuels for neurons when there is a deficit of glucose
ATP
- adenosine (ado) triphophate
- form of utilizable chemical energy
ATP in coupled reactions
- ATP constantly used up and made
- Primary fuel provides energy to make ATP which provides energy to do work
- Not efficient process (60% released as heat)
ADP as an Autocrine/Paracrine signal
- Released from granules in activated platelets for clotting
- Functions as a hormone-like chemical messenger on specific cell-surface receptors
Energy in terms of Stimulation
- Red bull (caffeine and sugar): has both a primary fuel and stimulant (anti-fatigue energy)
- Methylxanthines: includes caffeine
Caffeine
- Both an antagonist at cell-surface adenosine receptors and an inhibitor of intracellular enzyme, cyclic AMP phophodiesterase
- Improves vigilance
- Readily crosses blood-brain barrier
- Resembles adenine base
Extracellular ATP involvement in sleep regulation
- Falling asleep: neurons and astrocyte cloud creates extracellular ATP to turn into adenosine for adenosine receptor
- Caffeine blocks this receptor
- Staying asleep: some signalling from astrocytes and neurons but no adenosine
- Caffeine does not affect staying asleep
Sleeping Brain Waves
- Brain waves always coming from CCN (sleep does not turn it off)
- Over the night: oscillates between slow-wave sleep and REM sleep
Sleep
- Cools the body and the brain
- Allows brain to be washed: astrocyte pods release tubes where cerebral fluid is pumped
Sleep Consolidation of Memory and Learning
- Short term memory and long term memory may be located in different areas
- Sleep improves learning and memory
- Slow-wave sleep improves hippocampal-dependent memory
- REM sleeps appears to improve amygdyla-dependent (emotional) memories
Metabolic Syndrome
- Mets
- Increased central adiposity (estimate of visceral fat)
- Increased serum triglycerides
- Low HDL cholesterol
- Increased systolic or diastolic blood pressure
- Elevated fasting blood glucose
- not a disease but a pre-disease factor
- no symptoms
- Syndrome: propensity to lead to something
Metabolic Syndrome Risk Factor For?
- Cardiovascular diseases
- Type 2 diabetes
- Non-alcoholic fatty liver disease
- Depression
- Impairment of memory and cognition
- Peripheral neuropathy
- Impaired lung function
- Autoimmune disorders
- Sleep disorders
- Colon cancer
- Kidney stones
Comprised CCN with Metabolic Syndrome
- Disruptions in at least 3 homeostatic systems
- Chronic inflammation
- Hormonal alteration
- Altered immune function
Gut Microflora and Metabolic Syndrome
- gut microbacteria promotes breakdown and absorption of fatty acids and polysaccharides
- obese individuals have very different microbiomes
Dealing with Metabolic Syndrome in Canada
- 34% of American adults meet criteria
- increases with age and BMI
- Lifestyle interventions
- Change the environment
- Find gene therapies
Homeostasis and Thermoregulation
- Set point: balance point of the thermoeffector temperature thresholds for on/off (36.2 - 37.8)
- Negative feedback loop: control center -> thermo-effector -> thermo-sensor -> control center
- Second loop for air conditioning
- With second loop: decrease in amplitude, and increase in frequency of pulses per unit time (more loops = tighter homeostatic control)
- Varies on a diurnal cycle too
- Set point declines with age
Information Flow in Human Thermoregulation
- Hypothalamus is coordinating centre controlling set point
- Body Temperature Factors: behaviour, metabolism, vascular smooth muscle, hair smooth muscle
- At least 2 different temperature sensors
Stress
- Anything that is a challenge to homeostasis
- Often multi-dimensional challenges
- Psychological tests have similar effects as exercise
- Double stress test has higher amplitude and longer recovery time
- Impair performance as all homeostatic functions are related to CCN and interconnected
Daily Variations in Set Points by Stress
- Sleep deprivation hyperexcites the amygdala
- Less variation in set point
- Same with minor brain injury
Predictable Range
- Healthy range that the variable will vary over a given time period
- Sudden challenges take us outside the predictive range
- Homeostatic processes bring variable back in range
Homeostatic Load
- Total activity of the CCN to bring all homeostatic parameters back to the set point/ within the predictive range
- Allostatic load
Reactive Range
The range of homeostatic disturbance your body can recover from
Reactive Scope
- Predictive range + reactive range = reactive scope
- the total healthy scope an individual can react to
- outside scope, may not return to homeostasis
Homeostatic overload
Above the reactive scope limit
Homeostatic Failure
Below the reactive scope limit
Stresses Accumulate
- Alcohol + cold day = safe, while alcohol + cold day + cold water = possible death
- High grade fever = low grade fever + hot day + exercise
Interaction between Variable for Reactive Scope
- Restoring one variable to its normal set point may compromise the ability to regulate another
- Homeostatic load is distributed across the CCN
Complexity in Biological Systems
- Good
- Optimized information processing/flow
Complexity and Body Temperature
- Measured using thermoprobe
- Decreased complexity: in critically ill, in premature infants, with age
Complexity and Brain Electric Activity
- Measured using EEG (one of four brain waves)
- Decreased complexity: in vegetative state, in anesthesia, in elderly, in Alzheimer’s disease
Complexity and Human Movements
- Measured using LEDs
- Decreased complexity: in knee with ACL deficiency, in Parkinson’s disease, in elderly
Complexity and Heart Rate Variability
- Measure using ECG (electrocardiogram)
- Decreased complexity: in aging, in smoking, in obesity, in shift work, in depression, in infection, in paraplegia, in polluted environments, in psychosocial stresses, in PTSD
Diminished Physiological Complexity
- measure of our ability to have information flow in our CCN
- we become more machine-like
- Severed edges, damaged nodes, traffic jams in information flow
Optimal information flow in CCN is critical for our ability to:
- closely control homeostatic set points
- adapt to challenges to homeostasis
- manage cumulative homeostatic load
- protect against homeostatic overload or failure
How to Affect Physiological Complexity
- Block information flow (remove edge)
- Distort sensation/perception (damage node)
- Increase traffic in network (traffic jam)
Physiological Complexity and Concussions
- normally after 7 days should be back to normal
- vulnerable to compounded damage from a second challenge to homeostasis for a period of greater than 21 days
- most second concussions occur within 10 days from first
- Post concussive syndrome: no nightmares of trauma
Aging: Use it of Lose it
- We use less of our mental and physical abilities as we age, and therefore lose these abilities over time
Reducing Dementia
- Years of schooling
- Cognitive activities
- Cognitive training
- Physical activity (at least 3 times a week)
- Not less brain damage with aging, but improving coping mechanism
Aging: It’s in our genes
- Genetic variation in longevity genes may influence lifespan
- Studying through animal models, genotyping young vs old subects, or longitudinal studies
Aging: Rate of living
- The normal wear and tear of life, compounded by abuses to the system, results in an accumulation of damage that is irreparable
Caloric Restriction
- can optimize the healthy lifespan but at the erisk of decreasing reproduction success
- Difficult to test on humans due to duration and compliance
- 30% caloric restriction in Rhesus monkey: lower CVD, diabetes, cancer, and sarcopenia
- Yo-yo effect
Lifestyle Choices
- Movement/rest
- Outlook (self)
- Eating/drinking
- Connecting (others)
Low Back Pain
- About 80% of Canadians will experience
- Major contributor to health care costs
- Second most common cause of doctor visits
- Most common in middle age
- No gold-standard for determining risk
Acute Low Back Pain
- Lasts less than 6 weeks
Chronic Low Back Pain
- Lasts more than 12 weeks
Risk Factors for Low Back Pain
- Genetics
- Environment
- Lifestyle (depression and anxiety)
- Healthcare behaviours
- Acute LBP (for chronic LBP)
Low Back Pain Origination
- Brain
- Spinal cord and nerves
- Vertebral discs
- Vertebral bones
- Lower back muscles/tendons/ligaments
- Other sources
Local vs. Referred Pain
- Local: discogenic pain
- Referred: Sciatica (radiates from butt down the leg to toes
Lyme Disease
- Infectious Disease
- Ticks: small parasites that can act as vectors, reside in grass/shrubs, latch onto humans, burrows into skin, bite and draw blood, and transfer bacteria
- Bacteria: Borrelia
- Symptoms: fatigue, fever, headaches, rash with bullseye (can vary from days to months to show)
- Difficult to diagnose with a blood test with over 100 different symptoms
- Treated with antibiotics to prevent from getting to chronic stage (anywhere from months to years)
- ELISA test and Western blot
- Second stage: neurological complications, numbness, paralysis of facial muscles, visual disturbances, decreased concentration, irritability, memory and sleep disorders
Rheumatoid Arthritis
- Auto-immune disease
- Joint: where two bones meet, covered by cartilage to move smoothly, lined by synovium which produced synovial fluid to nourish it and absorb shock
- Inflammation: protective response to tissue injury or invasion of foreign particle
- Inflammation inside and around joints, leading to pain, swelling, and stiffness
- Women have it a lot more often (between 30-60 most common)
- Not sure why it happens: perhaps a genetic predisposition with a second hit, factors like hormones, obesity, smoking, environmental
- Diagnosis involves medical exam plus blood test for antibodies
- Antibodies attack synovial joint fluid
- Treated with anti-inflammatory medication, drugs, and therapy (no cure)
Gastroesophageal Reflux Disease
- Anatomical/Trauma Disease
- Stomach acid flows back into esophagus (acid reflux) which irritates it
- Symptoms: heartburn, chest pain, difficulty swallowing, throwing up, lump in throat
- Caused by frequent acid reflux, when lower esophageal sphincter relaxes abnormally or weakens
- Risk factors: obesity, hiatal hernia, pregnancy, connective tissue disorders, delayed stomach emptying
- Triggers: smoking, large meals, certain foods, certain medications
- Can lead to narrowing of esophagus, sore in esophagus, and precancerous changes
- Most relieved through diet and lifestyle changes with some antacids (neutralize acid) and perhaps surgery
- Hiatal Hernia: upper part of stomach moves up into chest through a small opening in the diaphragm, weakens LES
- May be caused by high inflammation, that damages esophagus
