Respiration The ins and outs
Functions 1. To bring O 2 into the body and transfer it to the blood stream 2. To remove CO 2 Circulation and respiration work together to achieve these functions
Why Do We Need Oxygen? Oxygen acts as a fnal hydrogen acceptor in cell respiration Recall Cellular Respiration: C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O + ATP - ATP is the energy for the cell and therefore requires oxygen to be present for the energy to be released.
Respiratory Surface The surface through which gas exchange takes place Characteristics: 1. Thin walled for diffusion 2. Moist for dissolving gases 3. In contact with a source of O 2 4. In contact with a system that transports O 2
Respiration The process that involves: a) Inhaling and exhaling of air b) Exchange of gases between cells and environment c) Chemical reactions where O 2 used to release energy from food
Inspiration Rib cage moves up and out. Diaphragm and intercostal muscles contract. Diaphragm moves down and flattens Pressure in lungs decreases and air rushes in.
Expiration Rib cage moves down and in. Diaphragm and intercostal muscles relax. Diaphragm moves up. Pressure in lungs increases and air is pushed out.
Negative Feedback Cycle see curriculum online
Internal Respiration The exchange of gases between the blood and the tissues. Oxygen diffuses out of blood and into tissues. Carbon Dioxide diffuses out of tissues and into blood.
External Respiration Exchange of gases between the air and the alveoli in the lungs. Carbon dioxide diffuses out of blood and into the lungs (alveoli) Oxygen diffuses into the blood and out of the lungs (alveoli).
During external respiration, oxygen must travel through these structures (in the following order): 1. Nostril 2. Nasal cavity 3. Pharynx 4. Glottis 5. Larynx (includes vocal cords) 6. Trachea 7. Bronchus (pl. bronchi) 8. Bronchiole (pl. bronchioles) 9. Alveolar ducts 10. Alveolus (pl. alveoli) From here, oxygen enters the body through the capillaries, this is the start of internal respiration
1. Nostril Air enters the nostril Nostril has hairs and mucus Hairs trap large particles Mucus traps smaller particles, bacteria, and moistens the air
2. Nasal Cavity/Nose Separated from the mouth by a bony plate called the hard plate Turbinate bones: Extend into the nasal cavity to increase the amount of surface area Helps warm the air Functions: Air warmed, moistened and cleaned Lining of the nasal cavity contains many blood vessels that warms the air Secretes mucus which moistens and traps dust and particles Has cilia small hair like structures that trap particles
3. Pharynx Tube common to both respiratory and digestive systems Starts at the back of the nasal cavity and extends to the larynx (voice box)
Larynx Box like structure at opening of the respiratory pathway Formed by cartilage
Trachea Wind Pipe Tube that extends from the larynx into the throat Divides into two smaller tubes: Right bronchi Left bronchi Made of smooth muscle that has c-shaped rings of cartilage embedded Keeps the trachea from collapsing and ensures that it is always open
Trachea Diagram
Bronchi Supported by rings of cartilage Branch into smaller tubes The smallest tubes are the bronchioles Alveolar ducts: At the end of the bronchioles that lead into the alveoli Alveoli (s. alveolus): Air sacs where gas exchange takes place
Bronchi Diagram
Gas Exchange in Alveoli
Lungs Each bronchus with all of its bronchioles, alveolar ducts and alveoli is a lung No muscle Elastic Responds passively to the action of the ribs muscles and diaphragm Right lung: Larger than the left lung Has three lobes: upper, middle, and lower Left lung: Has two lobes: upper and lower
External Membranes of the Lungs There are two external membranes surrounding the lungs Parietal pleura Pulmonary pleura These two membranes have water sandwiched in between them This fluid is called interpleural fluid Indirectly connects the lungs to the ribcage
Lung Diagram
External Membranes of the Lungs Diagram
Mechanics of Breathing Involuntary: Proceeds without thought Voluntary: Control can occur but eventually you would get tired Involuntary would take over Diaphragm: Dome shaped muscle laying above the waistline Separates thoracic and abdominal cavities Thoracic cavity: is the space in your chest above the diaphragm Abdominal cavity: is the space of your abdominal area Intercostal muscles: Attach 12 ribs Have you ever eaten ribs before? Then you have been eating intercostal muscles
Diaphragm Diagram
Intercostal Muscles Diagram