Functions and Processes of the Respiratory System

Gas exchange

The primary function of the respiratory system (oxygen in, carbon dioxide out).

Functions of the respiratory system

Filter and moisten inhaled air, regulate blood pH, produce vocal sounds, house receptors for the sense of smell.

Five processes involved in gas exchange

Ventilation, External Respiration, Gas Transport, Internal Respiration, Cellular Respiration.

Nose breathing

Filters, warms, and humidifies the air, which protects the respiratory tract.

Path air takes to circulatory system

Air travels from the nose → pharynx → larynx → trachea → bronchi → bronchioles → alveoli → capillaries.

Site of gas exchange

The alveoli.

Cell layers carbon dioxide passes through

Two cell layers (alveolar and capillary walls).

Emphysema and oxygen intake

Emphysema damages alveoli, reducing the surface area for gas exchange, which limits oxygen intake.

Oxygen and carbon dioxide movement

Oxygen moves from high to low concentration (alveoli to capillaries) and carbon dioxide moves from capillaries to alveoli for exhalation.

Oxygen transport in blood

Bound to hemoglobin and dissolved in plasma.

Carbon dioxide transport in blood

Dissolved in plasma, bound to hemoglobin, and as bicarbonate ions.

Urge to breathe

The buildup of carbon dioxide prompts the urge to breathe because it affects blood pH and respiratory drive.

Gas particle collisions and pressure

More collisions increase gas pressure.

Force of gas particle collisions

Greater force of collisions results in higher gas pressure.

Container size and gas pressure

Smaller container size increases gas pressure.

Temperature and gas pressure

Higher temperature increases gas pressure.

Air inhalation during ventilation

The diaphragm and intercostal muscles contract, increasing thoracic cavity size, lowering thoracic cavity pressure below atmospheric pressure, allowing air to flow in.

Air exhalation during ventilation

The diaphragm and intercostal muscles relax, decreasing thoracic cavity size, raising thoracic cavity pressure above atmospheric pressure, pushing air out.

Breathing at higher elevations

The lower atmospheric pressure reduces the amount of oxygen available for gas exchange.

Chemicals in breath

Trace amounts of nitrogen, oxygen, water vapor, and other volatile compounds.

Parts of a neuron

Cell body, dendrite, and axon. Flow: Dendrite → Cell body → Axon.

Presynaptic neuron

A neuron that sends a signal across the synapse.

Postsynaptic neuron

A neuron that receives a signal across the synapse.

Role of a neurotransmitter

A neurotransmitter transmits signals between neurons across the synapse, the gap between neurons.

Functions of glial cells

Oligodendrocytes: Provide myelin in the CNS; Schwann cells: Provide myelin in the PNS; Astrocytes: Support neurons, help maintain the blood-brain barrier; Microglia: Act as immune cells in the CNS, cleaning up debris.

Myelin sheath effect

It speeds up the rate of impulse travel along the axon.

Multiple sclerosis

An autoimmune disease where the immune system attacks the myelin sheath, slowing or blocking nerve signals.

Resting neuron charge

Due to a higher concentration of negatively charged ions inside and positively charged ions outside.

Three steps of an action potential

Depolarization: Na+ channels open, Na+ enters, inside becomes more positive. Repolarization: K+ channels open, K+ exits, inside becomes more negative. Return to Resting State: Na+/K+ pumps restore original ion distribution.

Action potential movement

It triggers neighboring channels along the axon to open in a wave-like sequence, creating a continuous impulse.

Inhibitory neurotransmitter effect

It makes the neuron less likely to fire an action potential.

Excitatory neurotransmitter effect

It makes the neuron more likely to fire an action potential.

Divisions of the nervous system

Central Nervous System (CNS): Brain and spinal cord, processes information. Peripheral Nervous System (PNS): Nerves, carries messages to and from the CNS.

Types of neurons

Sensory neurons: Carry info from PNS to CNS. Interneurons: Carry info within the CNS. Motor neurons: Carry info from CNS to PNS (to muscles, glands, etc.).

Regions of the brain

Cerebrum: Controls higher brain functions (thought, memory, emotion). Cerebellum: Coordinates movement and balance. Brainstem: Controls basic life functions (breathing, heart rate).

CNS protection

Bones: Skull and vertebrae protect CNS from injury. Meninges: Protective membranes covering the brain and spinal cord. Cerebrospinal fluid: Cushions CNS, removes waste. Blood-brain barrier: Limits harmful substances entering the brain.

Alzheimer's Disease causes and symptoms

Cause: Brain cell death and protein buildup in the brain. Symptoms: Memory loss, confusion, personality changes.

Parkinson's Disease causes and symptoms

Cause: Loss of dopamine-producing cells in the brain. Symptoms: Tremors, stiffness, movement difficulties.

Psychoactive drugs effect

They alter neurotransmitter levels or activity, affecting mood, perception, and behavior.

Sensory information processing

The majority of sensory information processed in the cerebral cortex comes from the hands, face, and mouth.

Sensation and perception

Sensation: The detection of sensory stimuli by receptors. Perception: The interpretation of sensory information by the brain.

Perception differences

Perception is influenced by individual brain processing and previous experiences.

Perception

Influenced by individual brain processing and previous experiences.

Synesthesia

When sensory pathways cross, causing blended perceptions (e.g., seeing colors when hearing sounds).

Mechanoreceptors

Detect touch, pressure, and vibration.

Thermoreceptors

Detect temperature changes.

Nociceptors

Detect pain.

Photoreceptors

Detect light.

Chemoreceptors

Detect chemical changes (e.g., pH, taste).

Sensory adaptation

The process where receptors become less responsive to constant stimuli, allowing us to ignore unimportant stimuli and focus on new, potentially important changes.

General/Somatic Senses

Found throughout the body (e.g., touch, pain).

Special Senses

Located in specific organs (e.g., vision, hearing) and involve complex structures.

Function of mechanoreceptors in ligaments

Sense stretch and prevent overstretching.

Function of mechanoreceptors in muscles

Detect changes in muscle length, aiding in muscle coordination.

Outer Ear

Collects sound waves.

Middle Ear

Transmits sound vibrations to inner ear.

Inner Ear

Converts vibrations to nerve signals and assists with balance.

Mechanical Digestion

Physical breakdown of food (e.g., chewing).

Chemical Digestion

Breakdown of food by enzymes into absorbable molecules.

Path of food through the gastrointestinal tract

Mouth → Esophagus → Stomach → Small intestine → Large intestine → Rectum → Anus.

Accessory glands of the digestive system

Salivary glands, liver, gallbladder, pancreas.

Mucosa

Innermost layer of the digestive tract; secretes mucus and digestive enzymes.

Submucosa

Connective tissue; contains blood vessels and nerves.

Muscularis

Muscle layer; responsible for movement.

Serosa

Outermost layer; reduces friction with surrounding structures.

Peristalsis

Wave-like contractions that move food through the digestive tract.

Segmentation

Rhythmic contractions that mix and break down food within the intestines.

Function of the esophagus

To transport food from the mouth to the stomach via peristalsis.

Food broken down in the stomach

Proteins.

Functions of mucus in the stomach

Protects stomach lining.

Functions of hydrochloric acid (HCl) in the stomach

Breaks down food and kills bacteria.

Functions of digestive enzyme (Pepsin) in the stomach

Begins protein digestion.

Chyme

Partially digested food mixed with stomach secretions, which moves to the small intestine.

Function of the large intestine

Absorbs water and electrolytes, and compacts waste into feces.

Composition of feces

Water, undigested food, bacteria, cells from the lining of the intestines, and waste products.

Function of the rectum

Stores feces until elimination.

Function of the anus

Controls the expulsion of feces from the body.

Organ systems specializing in waste removal

Urinary, respiratory, and digestive systems.

Urinary system waste removal

Primarily removes nitrogenous waste (e.g., urea from protein breakdown).

Urinary system regulation

Regulates/maintains pH, water balance, electrolyte levels, and blood pressure.

Parts of the urinary system

Kidney: Filters blood and forms urine. Ureter: Transports urine from kidney to bladder. Bladder: Stores urine. Urethra: Transports urine from bladder out of the body.

Functional unit of the kidney

The nephron.

Parts of a nephron

Glomerular Capsule: Filters blood to form a filtrate. Tubules: Reabsorb needed substances and secrete waste. Collecting Duct: Concentrates urine and moves it to the renal pelvis.

Equation of urine formation

Excreted = Filtered - Reabsorbed + Secreted.

Urine movement through the ureter

By peristalsis (wave-like muscle contractions).

Main components of urine composition

Water, urea, and electrolytes.

Urine color when adequately hydrated

Pale yellow.

Kidney stone

A hard deposit of minerals and salts in the kidney.

Urinary tract infection (UTI)

A bacterial infection of the urinary system, more common in women due to a shorter urethra.