Tentative Schedule Until Midyears Monday Tuesday Wednesday Thursday Friday 2 Circulatory system (Start working on Carbon Journey ch. 2, due 1/8) 3 Circulatory system 6 Circ. system special topics Respiratory system 7 8 9 Resp. system special topics (Start working on Carbon Journey ch. 3, due 1/15) 10 Nervous system 13 Quiz on circ. and resp. systems 14 15 Endocrine system 16 (Start working on Carbon Journey ch. 4, due 1/23) 17 Wrap systems 20 No school 21 22 Short test on systems Review 23 24 Midyears start

how stuff gets around the body Unit 2, Topic 7: Circulation Circulatory system: how stuff gets around the body We’ve talked about materials getting into and out of cells, but how do they get around the body? The circulatory system is like a system of major highways, minor highways, and small roads in neighborhoods. 2

Unit 2, Topic 7: Circulation What’s in the blood? 45% cells 55% plasma

How does blood move around the body?

Blood vessels arteries arterioles capillaries venules veins veins Unit 2, Topic 7: Circulation Blood vessels arteries veins artery arterioles venules arterioles capillaries venules veins 5

Venules and veins: getting blood back to the heart Unit 2, Topic 7: Circulation Blood flows toward heart One-way valves prevent blood from flowing backwards. 6

Changes in blood flow

Unit 2, Topic 7: Circulation The heart is made of smooth cardiac muscle. Smooth muscle is involuntary muscle, meaning you cannot consciously alter its contractions or releases. The atria are thin walled; the ventricles are thicker muscle because they pump blood out to the lungs and the body. The left ventricle is even thicker and stronger than the right ventricle, because it must pump with enough force to get blood to all parts of the body.The heart contains valves between the atria and the ventricles to prevent backflow. The pumping of the heart is a cycle between contraction and relaxation. Red is oxygen rich blood and blue is oxygen poor blood. Think of this diagram as a mirror image. When I reference right and left sides, it is the person’s right and left sides, as if they are facing us. Blood returns to the atria of the heart and leaves from the ventricles. The ventricles are the main pumps. We’ll start in the right ventricle. The right ventricle pumps oxygen poor blood to the lungs through the pulmonary arteries to pick up oxygen and dump CO2. Gas exchange occurs by simple diffusion in the lungs. The now oxygenated blood returns to the heart via the pulmonary veins. It goes to the left atrium. From the left atrium, blood moves to the left ventricle. The left ventricle then pumps the oxygenated blood out to the body through the aorta, the biggest artery of the body (into the systemic circuit).

Unit 2, Topic 7: Circulation The heart is made of smooth cardiac muscle. Smooth muscle is involuntary muscle, meaning you cannot consciously alter its contractions or releases. The atria are thin walled; the ventricles are thicker muscle because they pump blood out to the lungs and the body. The left ventricle is even thicker and stronger than the right ventricle, because it must pump with enough force to get blood to all parts of the body. The heart contains valves between the atria and the ventricles to prevent backflow. A heart murmur is a “leaky” valve. The pumping of the heart is a cycle between contraction and relaxation.

Circulation patterns in the body

The Respiratory System Packet 7 part 2 The Respiratory System

What is respiration? CO2 O2 Cell ATP C6H12O6 Exchange of gases between the internal environment and the external environment Need O2 in (for cellular respiration) Need CO2 out (waste product) O2

Respiratory systems Mechanisms of gas exchange in organisms: Direct with the environment Tracheae Gills Lungs General characteristics of respiratory systems: Thin, moist surfaces Large surface area: volume ratio For diffusion to occur into and out of cells, there needs to be an aqueous solution. The greater the surface area the more efficient the exchange of gases. Tracheae The openings to the air along the body are called spiracles. The tracheae branch throughout the body into smaller tubes, tracheoles. Exchange of gases (diffusion) occurs over the moist ends of the tracheoles. Gills Blood flows in the opposite direction (in capillaries) as water moving over the gill surfaces. This countercurrent exchange maximizes the diffusion of oxygen into the capillaries. Fishes can remove 80% of the oxygen from the water with this system.

Lungs: Our system of gas exchange B E C Our respiratory system starts with a series of branching air tubes that move air into and out of the lungs. They end in tiny sacs called alveoli. The alveoli are composed of a single layer of connected epithelial cells. Epithelial cells line all of the bodies cavities. They provide a good barrier because they are highly selective of what can move in and out. For example, the epithelial cells lining the lungs are designed to allow for the simple diffusion of gases and water back and forth, but little else. D E F G I

Negative pressure breathing inhale exhale We breathe using a system called negative pressure. When your diaphragm contracts your ribcage expands. This increases the volume of the lungs, decreasing the pressure on the air inside the lungs. Much like with a concentration gradient, gases will move along their pressure gradients. Since the pressure in the lungs is lower than that of the surrounding air, air rushes in to fill the space. This is inhalation. When the diaphragm relaxes, the volume of the lungs decreases and air pressure increase. Then air rushes out of the lungs from high to low pressure. This is exhalation.

Alveoli Alveoli are tiny air sacs in the lungs. They are the sites of gas exchange. They are surrounded by capillaries, which are the tiniest of the blood vessels. Both alveoli and capillaries are lined by a single layer of epithelial cells. The blood coming from the heart has returned from the body and is full of CO2. It is low in oxygen, because the cells of the body have used oxygen in the ATP making process. Which do you think has a higher concentration of O2: the air in the lungs after inhalation or the blood coming from the heart? What about CO2? What is the most prevalent gas in your inhaled breath? The air that enters the lungs from the outside world is high in O2 and low in CO2 compared to the blood. Oxygen diffuses through the cells of the alveoli into the extracellular matrix and then through the cells lining the capillary into the blood stream. Once in the bloodstream, oxygen diffuses again into red blood cells. CO2 does the reverse process. In both cases, the gases are diffusing from high to low concentration naturally. This is simple diffusion because the small uncharged/nonpolar molecules can go right through the phospholipid bilayers. Alveoli are VERY delicate. If too dry, they stick together and then tear. To counteract this, the cells secrete surfactants. These are lipoproteins that act as lubricants to prevent sticking.

Moving gases into bloodstream After inhalation O2 passes from alveoli to blood by… CO2 passes from blood to alveoli by… The air that enters the lungs from the outside world is high in O2 and low in CO2 compared to the blood. Oxygen diffuses through the cells of the alveoli into the extracellular matrix and then through the cells lining the capillary into the blood stream. Once in the bloodstream, oxygen diffuses again into red blood cells. CO2 does the reverse process. In both cases, the gases are diffusing from high to low concentration naturally. This is simple diffusion because the small uncharged/nonpolar molecules can go right through the phospholipid bilayers.

Red blood cells and hemoglobin

Circulation of gases

Special Topics: infections, diseases, effects of smoking Respiratory System Special Topics: infections, diseases, effects of smoking

Common respiratory infections Pneumonia Bronchitis Pneumonia is an infection of the alveoli in the lungs. Symptoms include persistent cough, fever, chest pain, increased heart rate, and difficulty breathing. Often occurs as a secondary infection of viruses or bacteria following a cold or the flu, when your immune system is fatigued from fighting the first infection. Bronchitis is an inflammation and irritation of the bronchi and bronchioles of the lungs. This leads to overproduction of mucus to lubricate the area. Excessive mucus leads to persistent coughing in an attempt to clear the airways. Overall symptoms include persistent coughing and difficulty breathing. Often occurs as a secondary infection of viruses or bacteria following a cold or the flu, when your immune system is fatigued from fighting the first infection. Can also occur if lungs are irritated by environmental contaminants like smoke particulates and pollen.

Chronic Respiratory Diseases These are mostly caused by smoking or chronic exposure to air pollutants.

Asthma Severe allergic reaction Bronchioles go into spasms, constricting the air passages Excess mucus is produced, blocking airways

Cystic Fibrosis Genetic disorder that affects the structure of 1 protein. Chloride ions protein pumps in cells of the trachea don’t work Results in production of abnormally thick and sticky mucus Mucus builds up in lungs and pancreas People with this disorder live much shorter lives (now up to late 30s/early 40s, only a couple of decades ago, most died in childhood)

Smoking and the lungs Cigarette smoke: carbon dioxide and 4,000 toxic chemicals including… Benzene Ammonia Formaldehyde Arsenic Cyanide

Smoking and the lungs Smoking effects on: Cilia Mucus Immune cells Blood-oxygen levels Alveoli Causes cilia to stop moving (for 20 minutes) Increases amount of mucus in the air passages (cilia no longer clearing mucus) Kills immune cells on respiratory tract Decreases the amount of oxygen carried by blood Leads to tar build-up in your lungs Second-hand smoke also contains many toxins

Lung Cancer Tumors form in the lungs www.lungcancer.au.com