homeostasis + transport IB SEHS

Homeostasis

How the body’s organ systems, tissues, and cells work, and how their functions are integrated to regulate body’s internal environment, maintaining “normal” internal body conditions

The hypothalamus regulates

Blood pressure, heart rate, respiration, digestion, body temperature, thirst, interactions of nervous and endocrine systems, appetite, wake-sleep, and cardiac muscle tissue

Involved in regulating body processes

Endocrine and nervous systems, nerves are faster than hormones

Negative Feedback

Loops work to reverse a stimulus (usually for homeostasis)

Positive feedback

mechanisms enhance the stimulus

Components of a feedback mechanism

A stimulus, a receptor/sensor, a control center, and an effector

pH

the acidity level of the blood. Normal is 7.35-7.45

Carbond Dioxide

causes a drop in pH and an increase in H+

Drop in pH

causes increase in respiration (frequency and depth of breath)

Intrinsic

Internal, regulation of the heart by the heart

Sinoatrial (SA) Node

Generates electrical impulses, causes contraction of atria then stimulation of AV node, and regulated by Oxygen and Carbon Dioxide hormones

Atrioventicular (AV) node

Generates secondary impulse and causes contraction of ventricles

Extrinsic

External regulation of the heart

Parasympathetic

Vagus nerve, releases acetylchlorine, slowing down SA node

Sympathetic

Other nerves release epinephrine and norepinephrine, acting as the neurotransmitters, to speed up the heart

Adrenal glands

Controlled by endocrine system, release epinephrine and norepinephrine

Glucose

Present in the blood for cells to break down energy. When concentrations increase, pancreas releases insulin hormone and cells remove glucose from the blood. When concentrations decrease,pancreases releases glucagon and live breaks glycogen (polysaccharide storage) into glucose.

Insulin sensitivity

Cells are more affected by insulin (less insulin needed). Increases with Excercise.

Insulin Resistance

Cells are less affected by insulin (more insulin needed). Poor diet, low activity.

Thermoregulation

Relies on cardiovascular, muscular, nervous, and integumentary (skin) systems

Muscle contraction

converts chemical energy (food) into mechanical energy (movement) and most energy (80%) is lost to heat

Temperature of the body

Different at different locations and often is dynamic due to various factors

Body heat

Production increases with metabolic rate based on Exercise, hormones, ingestion, age, and sex. Can be lost due to conduction, convection, radiation, and evaporation

Non shivering thermogenesis

When the body increases metabolism (head production) without shivering as response to cold

Shivering

Muscle contractions to release heat, including body temperature

Sweating

Reduces body temperature through evaporative cooling

Sex differences

Biological males typically sweat more than biological females. High surface-area-to-volume equals faster cooling. Luteal phase of menstruation leads to higher temperature.

Diffusion

Passive movement from high to low concentration

Inhalation

The diaphragm muscle contracts and flattens, increasing the volume of lungs and lowers the pressure inside

Exhalation

The diaphragm muscle releases and returns to a dome like shape, decreasing the volume of the lungs and increasing the pressure inside the lungs

Internal intercostal muscles

Work to reduce chest cavity volume (exhale)

External intercostal muscles

work to increase chest cavity volume (inhale)

Air flow

Inthrough nasal cavity, then pharynx (throat), then larynx (vocal cords), trachea (windpipe), bronchus (major branches), and bronchioles (minor branches). The purpose of each of these is to warm, moisten, and filter air. No gas exchange

Gas exchange

Happens in the alveoli. Small sacs for large surface area to volume ratio and are attached to capillaries. Inspired air has lots of oxygen, little carbon dioxide.Oxygen diffuses into the blood (high conc. in alveoli, low in blood). Carbon dioxide diffuses out of blood (high conc in blood, low in alveoli). Expired air has less oxygen, more carbon dioxide. Differences increase with Excercise.

Tidal volume

Normal breaths, because you don’t use your entire lung volume with every breath.

Inspiratory Reserve Volume

Big inhales to maximum capacity

Expiratory reserve volume

Big exhales

Residual Volume

The air left over after your maximum exhale

Vital capacity

Inspiratory Reserve Volume + Expiratory Reserve Volume + Tidal Volume. Increases with height.

Total Lung Capacity

Vital Capacity + Residual Colume

Minute Ventilation

Volume of air exhaled per minute (tidal volumes x breaths per minute)

Lung size

The average is 5.5 L at 25 and 200 mL at birth. Typically, men have larger than females.

Hyperventilation

Quickly reduces arterial Carbon dioxide levels, causing reduced stimulus to breath. Rebreathing (into a paper bag for panic attacks) and breath holding both work off arterial Carbon Dioxide.

Blood functions

Transports gases, nutrients, waste, hormones, and heat

Blood volume

Totals about 5L in a 70 kg person

Plasma

55% of blood volume. Water and nutrients.

Platelets

Less than 1% of blood volume. Repair and clotting.

White blood Cells

Less than 1% of blood volume. Immune function. Leucocytes.

Red Blood Cells

40-45% of blood volume. Oxygen and Carbon Dioxide transport. Hematocrit

Bicarbonate

The form carbon dioxide mostly travels as

Oxygen mainly transported

through attachment to haemoglobin of red blood cells

Erythropoietin (EPO)

stimulates red blood cell production

Blood doping

Using someones own blood to increase red blood cell concentration. Synthetic Erythropoietin can also be used to illegally produce more red blood cells/haemoblobin.

Arteries

Carry blood away from the heart. Usually carry oxygenated blood to the body. THe Pulmonary ____ carries deoxygenated blood to the lungs. Usually higher pressure and thick muscular walls.

Veins

Carry blood toward the heart. The pulmonary ____ carries oxygenated blood from the lungs back to the heart. Lower pressure and contains valves to prevent backward flow.

Capillaries

Connect arteries to veins. This is where gas exchange happens (diffusion from high to low concentrations). Around the body, oxygen leaves the blood and carbon dioxide enters. In the lungs carbon dioxide leaves and oxygen enters.

Systemic circulation and pulmonary circulation

For oxygenation of the blood

The right atria

One of four heart chambers. Collects blood from the body. On top where blood collects.

The left atria

One of four chambers of the heart. Collects blood from lungs. On top where blood collects.

Right ventricle

One of four chambers of the heart. Pumps blood to the lungs. On the bottom where blood pumps out.

Left ventricle

One of four chambers of the heart. Pumps blood to the body. On the bottom where blood pumps out.

vena cava

Large veins that return blood to the heart form the body

aorta

sends oxygenated blood to systemic circulation

valves

exist between atria and ventricles, and ventricles and artery. Tricuspid is between right A and V. Mitral is between left A and V. Pulmonary is between right V and pulmonary artery. Aortic is between left V and aorta.

Cardiac muscle tissue

what the heart is primarily made up of

Cardiac hypertrophy

What people who do cardiovasecular excercise experience

Hypertrophy

Muscle growth. When done in the heart it is increased muscle in the left ventricle to make circulation to the body easier

Blood pressure

The force that the blood experts on the blood vessels. Force is different depending on artery (higher, measured) or vein (low). Pressure changes depending on if the heart is contracting or relaxing

Systole

Contracting phase of blood pressure. Higher pressure. Healthy reasting ____ic blood pressure is 90-120 mmHg

Diastole

The relaxing phase of blood pressure. Lower pressure. Healthy resting ____ic blood pressure is 60-80 mmHg

Smooth muscles surrounding arteries

Constrict or relax to change how much blood can flow

Blood flow

Increases through heart rate and stroke volume. Majority of incrase goes to muscles. Many other organs decrease in _____. Muscle goes from about 20% of ____ to about 84% during excercise. Kidney and liver decrease in both percentage and overall blood volume. Blood sent to tissue of the heartincreases in volume but roughly same percentage. The brain receives more blood, but lower percentage.

Cardiac output

Total volume (L) of blood pumped from the left ventricle per minute. heart rate (BPM) * stroke volume (mL) divided by 1000. Can increase 5x during exercise.

Stroke volume

Volume pumped by the left ventricle (systemic) for every beat of the heart. Increases during excercise as heart pumps more forcefully.

Fitness levels affect on CO

More trained individuals have higher stroke volume. This allows for lower heart rate to have equal cardiac output. Trained individuals are then able to have greater cardiac output while maintaining a lower heart rate.

Cardiovascular Drift

During sustained/prolonged Excercise. Cardiac output must remain the same. Due to increase in semperature/sweating, stroke volume decreases. Heart rate must increase to maintain cardiac output.

VO2 Max

The maximum rate oxygen can be brought in and used. It is measured by gas concentration of nhale/exhale. Increases during Excercise. The higher it is means higher trained athletes

Fick Equation

A-VO2 diff measure the concentration of oxygen in arteries compared to veins. Higher means more Oxygen used.