Gas exchange, respiration, coordination and response

Smoking harms the respiratory system by causing a faster breathing rate, reducing oxygen intake, affecting gas exchange, constricting blood vessels, and coating the trachea and bronchi.

Exercise increases breathing rate and volume, helping to quickly remove carbon dioxide and deliver oxygen to working muscles.

The CNS consists of the brain and spinal cord. It processes nervous impulses from the body and coordinates responses.

The PNS includes nerves that connect the CNS to other parts of the body, including sense organs, receptors, and effectors.

Sensory neurons carry information from sense organs to the CNS.

Relay neurons are located within the CNS, transmitting signals from sensory neurons to motor neurons.

Motor neurons carry signals from the CNS to effectors, causing responses like muscle contractions.

Breathing involves the diaphragm and intercostal muscles, which change the volume of the thorax and lungs, creating pressure differences for inhalation and exhalation.

Aerobic respiration uses oxygen to break down glucose, releasing energy for various cellular functions. It produces water, carbon dioxide, and energy.

Anaerobic respiration occurs without oxygen, breaking down glucose into lactic acid and producing less energy than aerobic respiration.

Both aerobic and anaerobic respiration produce waste products such as carbon dioxide and water.

Energy released during respiration is used for various cellular processes like muscle contractions, new molecule synthesis, cell division, and active transport.

Gas exchange requires a large surface area, short diffusion distance, good blood supply, and proper ventilation to efficiently deliver oxygen and remove carbon dioxide.

The respiratory system includes the nose, mouth, larynx, trachea, lungs, bronchi, bronchioles, and alveoli, all working together for gas exchange.

Alveoli are adapted for gas exchange with thin, permeable walls, moist lining, large surface area, and high concentration gradients.

Oxygen diffuses from the alveoli into the blood capillaries, while carbon dioxide diffuses from the blood capillaries into the alveoli due to concentration gradients.

Simple reflexes are rapid, automatic responses processed in the spinal cord, providing protection and quick reactions to stimuli.

The reflex arc follows the path: Stimulus → Receptor → Sensory Neuron → Interneuron (CNS) → Motor Neuron → Effector (Muscle or Gland)

Involuntary responses happen without conscious control, often for survival purposes, and involve various organs and glands.

Voluntary responses require conscious control and are regulated by the brain.

Sense organs detect stimuli, like light, sound, smell, taste, and touch, with a specific sensitivity to changes in the environment

The eye consists of the cornea, iris, pupil, lens, ciliary muscles, and retina, each playing a crucial role in vision.

Rods in the retina are sensitive to low light, while cones are responsible for color vision.

The pupil dilates in low light to allow more light in and constricts in high light to reduce the amount of light.

Pupil dilation and rod sensitivity enhance vision in low light conditions.

Hormones are chemical messengers produced by endocrine glands, transported by the blood to target organs, causing changes in their activity.

Adrenaline increases heart rate, breathing depth, pupil dilation, and promotes glucose release from the liver and muscles for energy.

Homeostasis is the maintenance of internal body conditions within a narrow range, ensuring optimal functioning.

The body regulates temperature through sweating, vasodilation, goosebumps, shivering, and vasoconstriction, working to maintain a stable internal temperature.

The hypothalamus acts as the body's thermostat, receiving information from heat receptors and initiating responses to maintain temperature.

Blood glucose levels are regulated by a negative feedback mechanism involving insulin, glucagon, and glycogen.

Insulin is responsible for lowering blood glucose levels by converting glucose into glycogen and storing it in the liver.

Glucagon raises blood glucose levels by converting glycogen back to glucose and releasing it into the bloodstream.