Physiology I

B3.2 Transport (pp 270-289)

• Be able to describe adaptations of capillaries for exchange of materials between blood and the internal or external environment

  • Thin, narrow diameter, branching

    • Large total surface area

  • Permeable walls

  • Transports blood thru all tissues in body besides eye lenses/cornea

  • 1 layer of endothelium cells

  • Basement membrane

    • Coating of extracellular fibrous proteins make gel filter

      • Allows small/medium sized particles to pass through (no macromolecules) 

• Be able to describe how the structures of arteries and veins supports their functions

  • Arteries

    • Carry pulses of high blood pressure away from the heart to the organs

    • 2 types of fibers make arteries strong enough to withstand high/variable blood pressure without bulging out and bursting

      • Elastin fibers

        • Store potential energy when stretched

        • recoils/squeezes blood when pressure falls

          • Reduces energy needed

      • Collagen fibers

        • Tough rope-like proteins

        • High tensile strength

    • Layers

      • Tunica externa

        • Connective tissue w/ collagen

      • Tunica media

        • Smooth muscle w/ elastin

      • Tunica intima

        • Smooth endothelium

          • Sometimes w/ elastin

  • Veins

    • Carry pulses of low blood pressure from the organs towards the heart

    • same layers as arteries

      • Thinner wall than arteries

    • Blood drains out of capillaries into the veins continuously

      • No pulse

    • Contains far less elastin and smooth muscle

    • Flexible and continuous pocket valves prevent backflow

    • Blood flow assisted by gravity and adjacent tissues/muscle contractions

• Be able to describe and evaluate different methods for measuring pulse rate

  • Methods

    • Pulseometer 

      • Electronic

    • Manual

      • Counting HR over given time

• Be able to outline causes and consequences of occlusion of the coronary arteries

  • Causes

    • Fatty deposits, called atheroma or plaque, build up and cause the coronary arteries to become narrowed or completely blocked

  • Risk factors

    • Hypertension

    • Smoking

    • Obesity

    • Saturated fat and cholesterol

    • Excessive salt

    • Alcohol

    • Sedentary lifestyle

    • Genetic predisposition

    • Old age

  • Consequences

    • Restricted blood flow leads to pain, aka angina, and shortness of breath

    • Calcium deposits can develop

    • Rough surfaces can lead to blood clots

    • Restricted oxygen can lead to a heart attack

• Be able to outline how water is transported from roots to leaves (or leaves to roots) during transpiration

  • Xylem used to transport water in plants

  • Water evaporates from stomata

  • Water adheres to cellulose in xylem

  • Cohesion between water molecules leads to transpiration pull of water from roots to leaves

  • Passive process 

• Be able to outline adaptations of xylem vessels for the transport of water

  • Column of cells from end to end

  • Continuous tubes

  • No membrane or organelles

  • When mature, xylem cells are dead

  • Walls are thickened with lignin

  • Able to withstand great pressures

• Be able to draw and label the distribution of tissues in the transverse section of a dicotyledonous stem AND root

  • stem

    • Vascular bundle

      • Xylem - transports water from roots to leaves

      • Phloem - transports sugars from leaves to roots

      • Cambium - produces more xylem and phloem

    • Epidermis - waterproofs and protects

    • Cotex - for support and photosynthesis

    • Pith - for bulking out the stem

• root

  • Epidermis - absorbs water and mineral ions from soil, often using long narrow outgrowths (root hairs)

  • Endothermis - inner skin of cells that water must pass through to reach the xylem

  • Cortex - unspecialized cells that bulk out the root to strengthen it/increase its surface area

• Be able to describe the release and reuptake of tissue fluid in capillaries

  • Continual process

  • Contains same substances as blood (no large protein molecules)

• Be able to describe the exchange of substances between the tissue fluid and cells in tissues

  • Glucose moves through sodium-glucose cotransporters

  • Amino acids move by active transport

  • Oxygen and carbon dioxide move by diffusion

• Understand that excess tissue fluid drains into lymph ducts

  • Excess tissue fluid drains into lymph ducts

• Be able to describe the differences between the single circulation of bony fish and the double circulation of mammals

  • Single circulation

• Animals such as fish

• Blood is pumped to the gills to get oxygen

  • Blood only goes through the heart once

• Water pressure keeps capillaries from bursting

• Heart

  • Only has two chambers so blood is not entirley kept seperate by oxygen levels

  • Lower efficiency/lower pressure

    • Adaptation to lower oxygen demand

• Double circulation

  • Double circulation

    • Mammals

    • Heart pumps blood to lungs and body with varying pressures

    • Two seperate circuits

      • Pulmonary and systemic 

        • Heart to lungs and back v. heart to body and back

      • Blood is transported around in blood vessels

    • Oxygenated blood and non oxygenated blood are kept seperate

• Be able to outline adaptations of the mammalian heart for delivering pressurized blood to the arteries

  • Branched network of bronchioles

  • Extensive capillary beds surround alveoli

  • Both capillaries + alveoli made of single layer of cells

  • Large surface area; 300mil alveoli in adult

• Be able to deduce stages in the cardiac cycle from a pressure diagram

Important vocabulary:  capillary, artery, vein, tunica externa, tunica media, tunica intima, lumen, endothelium, plasma, fenestrated capillaries, atria, ventricles, collagen, vasoconstriction, occlusion, atheroma, plaque, angina, thrombosis, hypertension, capillary action, lignin, xylem, phloem, cambium, cortex, pith, lymphatic vessel, atrioventricular valves, semilunar valve, septum, cardiac muscle, sinoatrial node, coronary vessels, diastole, systole

D3.3 Homeostasis (pp 721-728)

• Be able to describe the importance of homeostasis in an organism

  • Maintenance of a constant internal environment in the organism

  • One of the seven essential functions of life

  • Includes blood pH, blood osmotic concentration (water balance), blood glucose concentration, core body temp

• Understand the role of negative feedback loops in homeostasis

• Feedback loops monitor levels of a variable and correct changes

• Provide info ab the outcome of a process used to either amplify or inhibit the process

• Positive

  • Feedback increases the gap between the original set point and the new level

  • Rare

• Negative

  • Feedback decreases the gap, so the original level is restored

  • Keeps cells within ideal/ stable limits

  • Costs large amounts of energy

• Can include nervous system/endocrine system (glands which release hormones that are transported in the blood)

• Be able to describe the regulation of blood glucose levels through hormones

  • Isolets of langerhans in pancreas contains alpha and beta cells

  • Rising blood glucose levels

    • High glucose level detected by beta cells in pancreas

      • Insulin stimulates uptake of glucose in tissue cells (especially muscle cells)

        • Glucose used for cellular respiration

      • Liver stores glucose for glycogen

    • Blood glucose level declines to a set point; stimulus for insulin release diminishes and body returns to homeostasis

  • Declining blood glucose levels

    • Low blood glucose levels detected by alpha helix cells in pancreas

    • Glucagon (hormone)

    • Glycogen converted to glucose and released

    • Blood glucose levels rises to set point; stimulus for glucagon release diminishes and body returns to homeostasis

• Be able to outline the physiological changes that form the basis of type I and type 2 diabetes

  • Type I

    • “Early onset/insulin dependent”

    • Autoimmune disorder; immune system destorys beta cells of pancreas

      • Insulin not secreted by beta cells

    • Usually appears in childhood, sudden

    • Genetic

    • 10% of diabetics

    • Treatment

      • Insulin injections

      • Bionic pancreas

        • Tracks person’s blood glucose levels with continuous glucose monitor, automatically delivers hormone insulin when needed w/ insulin pump

  • Type II

    • “Non insulin dependent”

    • Failure of target cells to respond to glucose

      • Deficiency of insulin receptors/glucose transporters leads to elevated glucose levels

    • Can be genetic

    • Risk increased by

      • sugary/fatty diets

      • Obesity from overeating

      • Lack of exercise

    • Shows up in all ages (formerly “late onset”)

    • 90% of diabetics

    • Treatment

      • diet/exercise

        • Smaller more frequent meals

        • Higher fiber lower suger

      • Some cases require medicine

• Be able to discuss the incidence of diagnosed diabetes in different races and possible reasons for these differences

  • 'Diagnosed'

    • Access to healthcare

      • Poorer neighborhoods

      • Redlining 

        • #racism

    • Access to healthy food

      • Food deserts

• Be able to use thermoregulation as an example of negative feedback control

  • Youre a negative feedback loop >:(

  • Thermoregulation

    • Used to make sure the body is at a constant specific body temperature

    • Body is monitored by thermorecepters

      • Free nerve endings of specialized sensory neurons

      • Warm and cold receptors stimulated by temperature

        • These recepters send signals to start the process of vasodialation and vasoconstriction to return temperature to the set point

• Be able to describe thermoregulation mechanisms in humans

  • Body temperature is monitored by thermoreceptors

    • Free nerve endings of specialized sensory neurons

    • Two types

      • Cold (stimulated by low temps)

      • Warm (stimulated by high temps)

    • Two locations

      • In skin - peripheral

        • Influenced by external temps

      • Core of body - central

        • Includes hypothalamus

  • Responses to heat

    • Vasodialation

      • Arteriole walls relac, widens lumen, increases blood flow to skin, increases heat loss

    • Sweating

      • Glans secrete onto skin surface, evaporates

      • Solutes (ex. sodium) remains on skin

      • Heat energy required, so it cools the blood flowing through the slin

  • Responses to cold

    • Vasocosntriction

      • Arteriole walls contract, narrows lumen, reduces blood flow to skin, reduces heat loss

    • Shivering (includes teeth chattering)

      • Many small, rapid muscle contractions produce heat

      • Mitochondria produces more atp, leading to more cellular respiration; byproduct of that is heat

    • Hair erection/goosebumps (unhelpful for humans)

      • Erector muscles make hair stand up, traps air to insulate

    • Uncoupled respiration in brown adipose tissues

      • Cells have less fat, more mitochonria

      • Mitochondria produces all heat, no ATP

  • Response to drop in body temp

    • Thyroxin increases metabolic rate of cells -> heat released -> increases body temp

    • Main targets are liver, muscle, brain cells

Important vocabulary:  homeostasis, negative feedback loop, pancreas, insulin, glucagon, islets of Langerhans, alpha and beta cells, autoimmune disorder, thermoreceptors, hypothalamus, vasoconstriction, vasodilation, brown adipose tissue, uncoupled respiration

Extended Response Questions to Prepare: On the day of the test your class will pick 3 numbers from a hat and you will write on 2. Six points each.

1. Distinguish between arteries, veins, and capillaries in structure and function. List what blood transports.

2. Capillaries

   1. Thin, narrow diameter, branching

   2. Permeable wall

   3. One layer of endothelium cells

   4. Basement membrane - coating of extracellular fibrous proteins make a gel filter

      1. Allows small/medium particles to pass through

   5. Pores between endothelium cells - allows fluid to leak

      1. Similar to blood plasma (tissue fluid)

3. Blood transports

   1. Plasma

      1. 55% blood vol

      2. Liquid matrix in which cells are suspended

      3. Contains electrolytes (inorganic salt ions), plasma proteins for clotting, buffers, escorts for liquids

   2. Red blood cells

      1. 99.8% blood cells

      2. Transports oxygen with hemoglobin (protein with iron) to bind to oxygen

   3. White blood cells

      1. For defence

      2. Phagocytes

      3. Lymphocytes

   4. Platelets

      1. Fragments of cells that help with clotting

4. Chat gpt answer

• Distinction Between Arteries, Veins, and Capillaries

  • Arteries

    • Structure:

      • Thick, muscular, and elastic walls

      • Narrow lumen (inner space)

      • No valves (except in the aorta and pulmonary artery)

    • Function:

      • Carry oxygen-rich blood away from the heart (except pulmonary artery)

      • Handle high-pressure blood flow

      • Help regulate blood pressure

  • Veins

    • Structure:

      • Thinner walls with less muscle and elasticity

      • Wider lumen

      • Contain valves to prevent backflow

    • Function:

      • Carry oxygen-poor blood toward the heart (except pulmonary vein)

      • Operate under low pressure

      • Assist blood return using skeletal muscle contractions

  • Capillaries

    • Structure:

      • Extremely thin walls (one cell thick)

      • Narrow diameter, allowing only one blood cell to pass at a time

      • No valves

    • Function:

      • Facilitate gas, nutrient, and waste exchange between blood and tissues

      • Connect arteries to veins

      • Enable diffusion of oxygen and carbon dioxide

• What Blood Transports

  • Oxygen (from lungs to tissues)

  • Carbon dioxide (from tissues to lungs)

  • Nutrients (e.g., glucose, amino acids, fatty acids)

  • Hormones (from glands to target organs)

  • Waste products (e.g., urea to kidneys for excretion)

  • Immune cells & antibodies (for defense against pathogens)

  • Heat (to regulate body temperature)

  • Platelets & clotting factors (for wound healing)

• Outline the regulation of blood glucose as an example of the role of hormones in homeostasis. Discuss the causes and treatment of Type I and Type II Diabetes.

  • Regulation of blood glucose

    • Islets of langerhans in pancreas contain alpha and beta cells (cells producing hormones glucagon and insulin respectively)

    • Rising blood glucose levels

      • High glucose level detected by beta cells in pancreas

        • Insulin stimulates uptake of glucose in tissue cells (especially muscle cells)

          • Glucose used for cellular respiration

        • Liver stores glucose for glycogen

      • Blood glucose level declines to a set point; stimulus for insulin release diminishes and body returns to homeostasis

    • Declining blood glucose levels

      • Low blood glucose levels detected by alpha helix cells in pancreas

      • Glucagon (hormone)

      • Glycogen converted to glucose and released

      • Blood glucose levels rises to set point; stimulus for glucagon release diminishes and body returns to homeostasis

  • Type I diabetes

    • Causes

      • Autoimmune disorder in which the immune system destroys beta cells of the pancreas

        • Causes insulin to not be secreted by beta cells

      • genetic

    • Treatment

      • Insulin injections

      • Bionic pancreas

        • Tracks person’s blood glucose levels with a continuous glucose monitor

        • Automatically delivers hormone insulin when needed using an insulin pump

  • Type II diabetes

    • Causes

      • Failure of target cells to respond to glucose

        • Deficiency of insulin receptors and glucose transporters leads to elevated gluose levels

      • Genetic (can be)

      • risk factors

        • Sugary and fatty diets

        • Obesity from overeating

        • Lack of exercise

    • Treatment

      • Diet and exercise

        • Smaller, more frequent meals

        • More fiber and less sugar

      • Some cases require medication

• Draw the plan diagrams for a root and stem. Label the structures and describe their functions.

  • Root

    • Epidermis

      • Absorbs water and mineral ions from soil, often using long narrow outgrowth

    • Endodermis

      • Inner skin of cells that water must pass through to reach the xylem

    • Cortex

      • Unspecialized cells that bulk out the root to strengthen it and increase its surface area

    • Xylem

      • Transports water from the roots up to the stem and leaves

    • Phloem

      • Transports sucrose/sugars from the leaves to the roots

  • Stem

    • Xylem

      • Transports water from roots to leaves

    • Phloem

      • Transports sucrose from leaves to roots

    • Cambium

      • Produces more xylem and phloem

    • Epidermis

      • Provides waterproofing and protection

    • Cortex

      • Provides support and photosynthesis

    • Pith

      • Bulks out the stem

• Outline the causes, risk factors and consequences of occlusion of the coronary arteries/coronary heart disease.  Make it clear what occlusion is and why it is so significant in coronary arteries in particular.

  • Causes

    • Fatty deposits, called atheroma or plaque, build up and cause the coronary arteries to become narrowed or completely blocked

  • Risk factors

    • Hypertension

    • Smoking

    • Obesity

    • Saturated fat and cholesterol

    • Excessive salt

    • Alcohol

    • Sedentary lifestyle

    • Genetic predisposition

    • Old age

  • Consequences

    • Restricted blood flow leads to pain, aka angina, and shortness of breath

    • Calcium deposits can develop

    • Rough surfaces can lead to blood clots

    • Restricted oxygen can lead to a heart attack

  • Significance

    • The coronary arteries supply oxygen and nutrients to the heart

    • Heart needs constant oxygen to pump blood to all the organs

• Outline thermoregulation as an example of negative feedback control and describe thermoregulation mechanisms in humans.

  • Thermoregulation

    • Body temperature is monitored by thermoreceptors, which are the free nerve endings of specialized sensory neurons

      • Two types; cold and warm

      • Two locations; in skin (peripheral) and core of body (central)

    • Example: increased body temperature

      • Thermoreceptors sense this stimulus

      • The body then uses vasodilation or sweating as thermoregulation mechanisms to cool down

      • Body temperature decreases, gap between imbalance level and original level is decreased, back to homeostasis

  • Thermoregulation mechanisms in humans

    • Responses to heat

      • Vasodilation

        • Arteriole walls relax

        • Widens lumen

        • Increases blood flow to skin

        • Increases heat loss

      • Sweating

        • Glands secrete onto skin surface and water evaporates

        • Solutes (like sodium) remain on skin

        • Heat energy is required, so cools blood flowing through the skin

    • Responses to cold

      • Vasoconstriction

        • Arteriole wals contract

        • Lumen narrows

        • Reduced blood flow to skin

        • Heat loss reduced

      • Shivering

        • Many small rapid muscle contractions produce heat

        • Mitochondria produces more atp, so more cellular respiration, byproduct of that is heat

      • Hair erection/goosebumps

        • Unhelpful for humans

        • Erector muscles make hair stand up, traps air inside to insulate

      • Uncoupled respiration in brown adipose tissues

        • Cells have less fat and more mitochondria

        • Mitochondria produces all heat, no atp

      • Body temp drops: Hypothalamus gives signal to pituitary gland which yaps to the thyroxin to increase, also increases metabolic rate

      • Blood temp drops: Thyroxin increases metabolic rate of cells, heart is released to increase body temp