Human Biology Respiratory System

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Margery Patrick
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1 Human Biology Respiratory System Respiratory System Responsible for process of breathing Works in cooperation with Circulatory system Three types: 1. Internal Respiration 2. External Respiration 3. Cellular Respiration 1

2 1. External Respiration Exchange of OXYGEN & CARBON DIOXIDE in the alveoli of the lungs 2. Internal Respiration Exchange of gases b/w the capillaries and the tissue fluid 2

3 3. Cellular Respiration Cells use oxygen to burn glucose to produce ATP energy and the waste products of CO 2 and H 2 O Recall. this is by mitochondria in cells The bits and pieces 3

4 Nasal Cavity Air enters through nostrils (nares) Lined with cilia and hairs that trap and filter dust and debris Air is warmed before it enters lungs by the rich blood supply that surrounds the cavity Inspiration and Expiration occurs through nose Pharynx Common passage for respiratory and digestive systems Warm, moist air moves to back of mouth Epiglottis (flap) opens when we breathe Glottis (opening to larynx) is now open 4

5 Larynx Aka. Voice Box Contains vocal cords Located below the epiglottis Acts as a passageway for air b/w pharynx and trachea Trachea Aka. Windpipe Has rings of cartilage around it = STRENGTH! Carries air b/w larynx and bronchi Lined with cilia and mucus Cilia beat to remove mucus and dust inhaled 5

6 Bronchi 2 tubes that branch from trachea INTO lungs Bronchioles Smaller passageways that branch off bronchi Carry air to ALVEOLI Each bronchiole supplies air to a lobule within the lung 6

7 Alveoli Small, thin-walled air sacs within the lungs This is where GAS EXCHANGE occurs The diffusion of oxygen into lungs AND carbon dioxide out Has a large SA:Volume ratio! Lined with a lipoprotein layer (=pulmonary surfactant) Prevents alveoli from collapsing when air leaves Alveoli 7

8 Alveoli 8

9 Thoracic Cavity Enclosed space within the ribcage This cavity allows breathing to take place Protects the heart, large blood vessels, and other vital organs Diaphragm is at the bottom of the cavity Pleural Membrane Two layers that lie between the lungs and chest wall Inner membrane Encases lungs Outer membrane Prevents friction and allows easy movement between lungs and chest wall Complete seal and low pressure between these membranes prevent lungs from collapsing 9

10 Diaphragm Dome-shaped muscle Separates thoracic cavity and abdominal cavity When it contracts: Muscles shorten and flatten out the diaphragm Increases the volume of the thoracic cavity & pushes down on the abdomen 10

11 11

12 Breathing Humans breathe 15-20x per minute 500mL of air is exchanged with each breath = tidal volume Breathing - Here s How! Nervous Control Respiratory center is within the MEDULLA OBLONGATA (brain stem) Part of the autonomic system 12

13 1. CO 2 levels in blood will increase as cells continue to produce it [CO 2 increases until it reaches a threshold level] 2. Chemoreceptors in arteries detect increased CO 2 and H + levels 3. Chemoreceptors send signal to medulla oblongata 4. Chemoreceptors (in aorta and carotid arteries) respond to [H+] and also CO 2 & O 2 in blood These bodies communicate with respiratory center 5. During inhalation (inspiration) we breathe IN air 6. Medulla oblongata sends nerve impulse to diaphragm and muscles in rib cage Diaphragm CONTRACTS and LOWERS Rib muscles (intercostals) CONTRACT Rib cage moves UP and OUT * These movements increase VOLUME of thoracic cavity causing a lower pressure in lungs than air pressure Creates a partial vacuum (NEGATIVE PRESSURE) THIS POWERS BREATHING!!!! 13

14 7. Lungs expand and air flows into ALVEOLI 8. Stretch receptors in alveoli wall detect expansion (or stretching) of alveoli 9. Medulla is notified by receptors when a certain inflation has been reached (inhalation stops) 10. Inhibitory message sent to medulla oblongata causes the center to stop sending a message to diaphragm and rib muscles - contraction ceases Diaphragm RELAXES and resumes normal dome shape Intercostals RELAXES Rib cages RELAXES These movements DECREASE the VOLUME of thoracic cavity Pressure in lungs increases and air is forced out of lungs! POSITVE PRESSURE in lungs results Volume of lungs decrease and air is forced out (EXHALATION / EXPIRATION) 14

15 SUMMARY - INHALATION Diaphragm - contracts, pulls down and flattens Intercostals - Contract Ribs - Lift UP and OUT Thoracic Cavity - increases in size Lungs expand Negative Pressure results in air flows INTO lungs SUMMARY - EXHALATION Stretch receptors max out Diaphragm - relaxes, pulls UP and resumes DOME SHAPE Intercostals - RELAX Ribs - move DOWN Thoracic Cavity - decreases in size Lung volume DECREASES POSITIVE Pressure results in air flows OUT of lungs 15

Blood vessels constrict and reduces flow of O 2 to the brain

16 Hyperventilation When you breathe too deeply or too rapidly You exhale too much CO 2 Blood ph becomes more ALKALINE Blood vessels constrict and reduces flow of O 2 to the brain Leads to rapid, shallow breathing Cure - take slow deep breathes 16

17 O 2 is carried in the blood: Carried directly on hemoglobin as OXYHEMOGLOBIN Hb + O 2 HbO 2 CO 2 is carried in the blood: (3 Ways) 1) Bicarbonate Ion (HCO 3- ) - 70% of CO 2 is transported this way - Bicarbonate ions react with hydrogen ions released from reduced hemoglobin to form carbon dioxide and water (exhaled) carbonic anhydrase HCO H > H 2 CO > CO 2 (exhaled) + H 2 O bicarbonate ion + hydrogen ion > carbonic acid -----> carbon dioxide + water 17

18 CO 2 is carried in the blood: (3 Ways) 2) CO 2 dissolved directly in blood plasma - 5% of CO 2 CO 2 is carried in the blood: (3 Ways) 3) Carried by hemoglobin - as Carbaminohemoglobin (HbCO 2 ) - 25% of CO 2 HbCO > Hb + CO 2 (exhaled) carbaminohemoglobin hemoglobin carbon dioxide 18

19 More about Hb: affected by ph, temp. and [O 2 ] 1. Hb picks up O 2 more easily at a BASIC or NEUTRAL ph and LOWER TEMP Conditions at lungs 2. Hb drops O 2 more easily at a more ACIDIC ph and WARMER temp Conditions at tissues More about Hb: Carbon Monoxide Carbon monoxide (CO) Toxic gas Colourless, ouderless, tasteless, non-irritating Hard to detect CO bonds to Hb 200x more than Oxygen Thus, if we take in too much CO, than Hb cannot carry oxygen to our body and our body slowly shuts down (hypoxic tissue injury) 19

Chapter 11: Respiratory System Review Assignment

Name: Date: Mark: / 45 Chapter 11: Respiratory System Review Assignment Multiple Choice = 45 Marks Identify the choice that best completes the statement or answers the question. 1. Which of the following