Studied by 0 people
Looks like no one added any tags here yet for you.
What is the main role of the endocrine system?
It regulates body functions through chemical messengers to maintain balance.
How do hormones regulate homeostasis with the nervous system?
Hormones provide slow, long-lasting control, complementing rapid nervous responses.
How do hormones reach and affect target cells?
Hormones travel through the bloodstream, bind to specific receptors, and trigger cell actions.
What is downregulation?
A decrease in receptor numbers in response to high hormone levels.
What is upregulation?
An increase in receptor numbers in response to low hormone levels.
What are the characteristics of steroid hormones?
They are lipid-soluble and directly influence gene expression in cells.
How do steroid hormones act on target cells?
They enter cells, bind to receptors, and activate DNA to produce proteins.
What are the characteristics of non-steroid hormones?
They are water-soluble and act through cell membrane receptors.
How do non-steroid hormones affect target cells?
They use second messengers to initiate changes in the cell.
What are prostaglandins?
Localized chemical messengers that regulate inflammation, pain, and other functions.
Which hormones regulate metabolism during exercise?
Growth hormone, thyroid hormones, catecholamines, cortisol, insulin, and glucagon.
Where are these hormones released from?
From glands like the pituitary, thyroid, adrenal glands, and pancreas.
What do hormones regulating CHO metabolism do?
They balance blood sugar by promoting glucose release or uptake during exercise.
How do insulin and exercise affect glucose uptake?
Exercise enhances glucose uptake independently of insulin.
What are the two phases of glycogen synthesis?
Rapid initial synthesis followed by a slower, prolonged phase.
How is fat metabolism regulated during exercise?
Hormones increase fat breakdown as exercise duration extends.
Which hormones regulate hunger?
Hormones like leptin, ghrelin, and insulin from fat, stomach, and pancreas.
What is leptin resistance, and how does it lead to obesity?
A reduced response to leptin, causing overeating and weight gain.
Functions of the cardiovascular system
Transport nutrients, oxygen, and hormones; remove waste; regulate temperature.
Difference between ventricles and atria
Atria receive blood; ventricles pump blood out of the heart.
Blood flow from capillaries back to the heart
Capillaries → veins → heart → lungs → heart → arteries → muscles.
Myocardium
Striated like skeletal muscle but contracts involuntarily like smooth muscle.
Coronary arteries
Supply blood to the heart; atherosclerosis blocks flow and causes damage.
Intrinsic control of the heart
Specialized cells regulate the rhythm without external signals.
Electrical path through the heart
SA node → AV node → bundle of His → Purkinje fibers.
Intrinsic heart rate
Natural rate set by the SA node; nerves and hormones can increase it above 100 bpm.
Extrinsic factors affecting heart rate
Neural, hormonal, and environmental factors like stress and exercise.
Measurement of heart activity
Using an ECG with phases: P wave, QRS complex, and T wave.
Stroke volume
Blood ejected per beat.
Ejection fraction
Percentage of blood pumped out per beat.
Cardiac output
Blood pumped per minute.
Cardiac cycle
Repeating phases of heart contraction (systole) and relaxation (diastole).
Components of the vascular system
Arteries, veins, and capillaries.
Normal blood pressure
120/80 mmHg; measured with a cuff and stethoscope or device.
Driving force of blood flow
Pressure gradients and vascular resistance.
Vasoconstriction and vasodilation
Narrowing and widening of blood vessels to regulate flow.
Blood pressure measurement
Using a sphygmomanometer to record systolic and diastolic pressure.
Blood distribution at rest and exercise
Rest: more to organs; exercise: more to muscles.
Intrinsic control of blood flow
Local factors like oxygen demand and vessel stretch.
Metabolic, endothelial, and myogenic mechanisms
Response to oxygen and nutrient needs; signals from blood vessel lining; muscle response to pressure changes.
Sympathetic nervous system effect on blood flow
Increases flow to muscles and reduces flow to non-essential areas.
Blood distribution percentage at rest
Most is in veins (60%), with smaller amounts in arteries and capillaries.
Reflexes controlling blood pressure
Baroreceptors respond to pressure changes, altering heart rate and vessel tone.
Mechanisms returning blood to the heart
Muscle pumps, valves in veins, and breathing mechanics.
Functions of blood
Transport, immunity, clotting; volume: 5-6 liters in men, 4-5 liters in women.
Components of blood
Plasma (55%), red blood cells (45%), white cells and platelets (<1%).
Lack of a nucleus in red blood cells
Maximizes oxygen transport but prevents repair.
Hemoglobin
A protein in red blood cells that binds oxygen for transport.
Blood viscosity effect
Higher viscosity slows flow and increases heart workload.
Main job of the respiratory system
To exchange oxygen and carbon dioxide between the body and the environment.
Pulmonary ventilation
Movement of air in and out of the lungs: nose/mouth → trachea → bronchi → alveoli → capillaries.
Anatomy of the pulmonary system
Includes the nose, trachea, bronchi, lungs, alveoli, and respiratory muscles.
Inspiration process
Active process using the diaphragm and external intercostals.
Expiration process
Passive at rest, using elastic recoil; active during exercise, using internal intercostals and abdominals.
Boyle's Law
Pressure and volume are inversely related, aiding airflow.
Dalton's Law
Total pressure equals the sum of partial pressures.
Henry's Law
Gas dissolves in liquid based on pressure and solubility.
Fick’s Law
Diffusion rate depends on surface area and gas gradient.
Respiratory pump
Changes in thoracic pressure during breathing assist venous blood return to the heart.
Pulmonary diffusion
Exchange of gases between alveoli and pulmonary capillaries.
Partial pressures of gases in air
Oxygen: 159 mmHg, Carbon dioxide: 0.3 mmHg, Nitrogen: 600 mmHg.
Importance of partial pressure
Drives gas exchange in the lungs and tissues.
Partial pressure gradients for gases
Oxygen: High in alveoli (105 mmHg), low in blood (40 mmHg); Carbon dioxide: High in blood (46 mmHg), low in alveoli (40 mmHg).
Oxygen diffusion during rest and exercise
Increases during exercise due to higher oxygen demand and stronger gradients.
Factors affecting oxygen capacity
Hemoglobin levels, partial pressure, and lung surface area.
Oxygen transport in the body
Bound to hemoglobin (98%) and dissolved in plasma (2%).
Temperature and pH effect on oxyhemoglobin saturation
Higher temperature and lower pH shift the curve right, reducing affinity for oxygen.
Oxyhemoglobin saturation comparison at rest and exercise
Lower during exercise to release more oxygen to tissues.
Carbon dioxide transport in the body
Bicarbonate (70%), bound to hemoglobin (20-23%), dissolved in plasma (7-10%).
(a-v) O2 difference variation
Greater during exercise as muscles extract more oxygen.
Myoglobin
A muscle oxygen carrier with a steeper curve and higher affinity for oxygen than hemoglobin.
Ventilation regulation mechanisms
Peripheral: Chemoreceptors and stretch receptors; Central: Respiratory centers in the brainstem.
Note 
Flashcard (127)