Open vs Closed Circulatory Systems

Open vs Closed Circulatory Systems

• Open: No distinction between circulating and extracellular fluid. This fluid is called hemolymph. The heart pumps hemolymph, but tissues like wing muscles receive oxygen directly from tracheae.
• Closed: Distinct circulatory fluid enclosed in blood vessels and transported to and from the heart. The heart pumps blood to arteries which carry blood away from the heart. Arteries branch into capillaries where gas exchange occurs. Veins return blood to the heart.

Oxygen & Carbon Dioxide

• Gas Exchange: Consists of 5 major steps:
  • Ventilation: Movement of air or water through a specialized organ like lungs or gills.
  • Diffusion at respiratory surface: Oxygen moves from air/water into blood and CO2 moves from blood into air/water.
  • Circulation: Transporting dissolved oxygen and CO2 throughout the body via the circulatory system.
  • Diffusion at tissue: Oxygen moves from blood into tissue and CO2 moves from tissue into blood.
  • Cellular respiration: Cells use oxygen and produce carbon dioxide.

Bronchi vs. Bronchioles

• Bronchi: Narrow tubes that carry inhaled air to the lungs, branching off from the trachea.
• Bronchioles: Even narrower tubes that branch off from the bronchi within the lungs.

Alveoli

• Tiny sacs within mammal lungs that greatly increase surface area for gas exchange.

Inhalation & Exhalation

• Inhalation: Diaphragm contracts, moving down and lowering pressure in the chest cavity. This causes lungs to expand and air to move in.
• Exhalation: Diaphragm relaxes, chest cavity decreases (ribs relax), and air is exhaled.

Types of Blood Vessels

• Arteries: Tough, thick-walled vessels that carry blood away from the heart under high pressure.
• Capillaries: Vessels with walls only one cell thick, allowing gas exchange between blood and tissues. Form capillary beds.
• Veins: Thin-walled vessels that return blood to the heart.

Anatomy of a Neuron

• Dendrite: Receives chemical signals and converts them into electrical signals.
• Axon: Conducts electrical signals.
• Cell Body: Integrates incoming electrical signals.

Action Potential

• Involves the transport of sodium (Na+) ions outside the axon and potassium (K+) ions inside.

Parasympathetic vs. Sympathetic Nervous Systems

• Parasympathetic: Promotes "rest and digest" functions that conserve or restore energy.
• Sympathetic: Prepares organs for stressful situations ( "fight-or-flight")

Human Brain

• Drug abuse: Can disrupt brain function and have long-term consequences.

Function of the Ear

• Inner Ear: Transforms vibrations for hearing and balance.
• Middle Ear: Transmits sound waves from the external environment to the inner ear.
• Outer Ear: Collects pressure waves and funnels them into the ear canal where they strike the tympanic membrane.

Eye Parts

• Cornea: Transparent sheet of connective tissue that helps focus light.
• Iris: Pigmented round muscle inside the cornea that controls the size of the pupil.
• Pupil: Hole in the center of the iris that allows light to enter the eye.
• Lens: Clear, curved structure that focuses incoming light onto the retina.
• Retina: Back of the eye where the cornea and lens focus light.

Lateral Line System

• Series of canals running along the head and body of fish. Water enters the canals through pores and bends kinocilia on hair cells which activate sensory neurons, helping fish detect water movement and vibrations.

Types of Sensory Receptors

• Mechanoreceptors: Respond to distortion caused by pressure.
• Photoreceptors: Respond to particular wavelengths of light.
• Chemoreceptors: Detect specific molecules.
• Thermoreceptors: Detect changes in temperature.
• Nociceptors: Sense harmful stimuli such as tissue injury.
• Electroreceptors: Detect electrical fields.
• Magnetoreceptors: Detect magnetic fields.

Sarcomere

• The basic functional unit of a muscle fiber.
• Actin: Composes thin filaments.
• Myosin: Composes the thick filaments.

Types of Muscles

• Smooth Muscle: Found in intestines and arteries, helps move food and regulate blood pressure.
• Cardiac Muscle: Found in the heart, pumps blood through the circulatory system.
• Skeletal Muscle: Attached to the skeleton, move the skeleton by contracting.

Types of Skeletal Systems

• Hydrostatic Skeletons: Use the hydrostatic pressure of enclosed body fluids or soft tissues to support the body.
• Endoskeletons: Have rigid structures inside the body, such as bones.
• Exoskeletons: Have rigid structures on the outside of the body like shells or chitinous armor.

Explore the key differences between open and closed circulatory systems in this informative quiz. Learn about the processes of gas exchange, including ventilation, diffusion, and circulation. Understand how oxygen and carbon dioxide are transported throughout the body.