Life's Transport and Exchange PDF

# Lesson 2: Life's Transport and Exchange ## The Need to Respire and Exchange Essential Gases ## Gas Exchange in Animals - **Respiration** - is the process of obtaining sufficient oxygen and expelling excessive amounts of carbon dioxide. - **Ventilation** - is the process involved in the bringing...

# Lesson 2: Life's Transport and Exchange ## The Need to Respire and Exchange Essential Gases ## Gas Exchange in Animals - **Respiration** - is the process of obtaining sufficient oxygen and expelling excessive amounts of carbon dioxide. - **Ventilation** - is the process involved in the bringing of oxygenated water of air into contact with respiratory organs. - **4 major types of gas exchange systems that allow them to obtain oxygen from the environment:** body surface, gills, tracheae, or lungs. 1. **Integumentary exchange or cutaneous respiration** - use of skin or body surface to exchange gases. 2. **Tracheal system** - uses fine air-conducting tubules called tracheoles that can become smaller enough, with tips that reach all its cells to carry out gaseous exchange. - consists of branched internal tubes that extend throughout the body. 3. **Gills** - are found in more advanced marine invertebrates and vertebrates; they are thin in sheets of tissues that waves through the water, increasing the surface area available for diffusion. - e.g. Fishes have a set of feather-like internal gills found of each side of its head that flap open and close with the exchange of gases. 4. **Lungs** - is used by higher forms of terrestrial vertebrates that are internally line with moist epithelium. - Air-breathing vertebrates have their lungs located inside the chest or thoracic cavity and protected by the rib cage. - e.g. Birds have a different level of activity and metabolic needs due to their flight abilities. They have respiratory demand greater than the capacity of the lungs of an active mammal. - The air that passing across the bird's lungs is always fully oxygenated and the blood flow is a 90-degree angle called crosscurrent flow. ## Gas Exchange in Plants Plants do the reverse of respiration by taking in carbon dioxide and expelling out oxygen through the process of photosynthesis. The exchange of gases in plants takes place mainly in the stomata of the leaves and young stems. Each of the stoma contains a pore at the center surrounded by two bean-shaped cells, called guard cells, that control the exchange of gases and prevent the plant from losing too much water. Like in the leaves, stomata in the stems called lenticels, as tiny openings are used for gas exchange. Plants also respire through their roots. The roots are covered by tiny outgrowths, called root hairs, which increase the surface absorptive capacity of the roots and provide a moist surface area for gas exchange. - e.g. In a mangrove environment where oxygen is poor and unstable, mangrove plants develop lateral breathing roots called pneumatophores. - **Negative geotropism** - roots grow upward or against gravity. - **Positive geotropism** - roots grow inward or toward gravity. # The Need to Transport Essential Materials ## Animal Transport System **Circulatory system** - allow animals to take in nutrients, exchange essential gases, and remove unwanted products. **2 types of circulatory system**: Open circulatory system and Closed circulatory system. **Open circulatory system** - fluid is pumped through open-ended vessels and transported among cells with no distinction between circulating fluid (blood) and the interstitial fluid. **Closed circulatory system** - blood is confined within the blood vessels separated from the interstitial fluid. - **Grasshopper** has a tubular heart, a muscular tube that pumps hemolymph though a network of channels into chambers and drains back to the central cavity. - has open circulatory system. - **Annelids**, such as the earthworm, possess the simplest closed circulatory systems, that consists of two main blood vessels connected to a series of heart-like structures called aortic arches. - **Fish**, has two main chambers organized into rows. Blood travels through this chambers and is pumped out through a ventral cavity into smaller capillaries in its gills where respiratory gas exchange occurs. ## Mammalian Circulatory System In humans, the closed circulatory system is also known as **cardiovascular system** (kardia means “heart”, and vasculum means “vessels”) consisting of four-chambered heart, blood and blood vessels that carry blood to every part of the body and the lymphatic systems. **Circulatory system's three principal functions:** 1. **Transportation** - transports three types of substances essential for cellular metabolism in the following forms: respiratory (oxygen and carbon dioxide), nutritive (nutrients in the form of food molecules), and excretory (metabolic wastes such as excess water and ions). 2. **Regulation** - transports hormones and participates in heat regulation. 3. **Protection** - protects our body from injury during blood clotting and plays a role in the immune defense against toxins and pathogenic organisms. **Human heart** - a muscular organ, positioned behind the rib cage and between the lungs, is the pump that pushes blood throughout the circulatory system. **Human heart** - **Right side** - pumps blood to the lungs to receive oxygen - **Left side** - pumps blood to the entire body. - **Septum** - a tissue wall that divides the heart in half and prevents blood from flowing between the two atria or two ventricles. - **Aorta** - is the major artery of the body, which, takes oxygenated blood to the organs and muscles. ## The Blood **Blood** is the collection of cells in the form of a fluid by which oxygen and nutrients reach body's cells and wastes materials carried away. **Blood** carries hormones, which control body processes, and cells that fight disease-causing microorganisms and produce antibodies to fight invading germs. **Composed of two components:** plasma (fluid portion) and the blood cells (red blood cells, white blood cells, and platelets). - About 55% of the blood is plasma (a pale yellowish liquid that is about 92% water. The remaining 8% is made up of a dissolved complex mixture or various substances. - **Karl Landsteiner** - an Austrian biologist, physician, and immunologist who discovered the human blood groups. - 3 types of cellular components suspended in the plasma of the blood. (Red blood cells, white blood cells, and platelets). ### Red Blood Cells - Also known as **erythrocytes**, that make up 44% of your blood transport oxygen and some carbon dioxide throughout the body. - **Male** - 5.5 million red blood cells per milliliter of blood. - **Female** - 4.5 million red blood cells per milliliter of blood. - **Red blood cell** has iron-containing protein known, as **hemoglobin**, that binds chemically to oxygen molecules. - **Bright red** - hemoglobin + oxygen - **Dark red** - without oxygen - Formed in the **red marrow** of bones. ## The Blood Vessels - **Arteries** - **Capillaries** - **Veins** ### Arteries - are blood vessels that move blood away from the heart. - two ventricles of the heart is connected to a major artery. - blood is pushed into the arteries with each contraction of the ventricles. - Artery's wall is generally very thick and consist of three layers of tissue. - smaller arteries, known as **arterioles**, are considered the finest, microscopically sized branches of the arterial trees. ### Capillaries - composed narrow and thin-walled tubes. - wall of most capillaries are only one cell thick, this allows oxygen and nutrients through capillary walls and into body cells and for carbon dioxide and other waste materials to diffuse through cell wall into the capillaries. - after traversing the capillaries, blood is collected via smaller blood vessels, called **venules**, that lead to larger blood vessels called veins. ### Veins - a blood vessel that move blood-carrying waste products toward the the heart. - blood that enters the vein flows more slowly and smoothly because the heart does not push blood through the veins. - Veins have one-way valves to keep blood from flowing toward the heart. - **A valve** is a flap tissue that prevents the backflow of blood and keeps its flow in one direction. # Plant Transport System **Marcelo Malpighi** - Italian scientist who discovered a sweet-tasting fluid that come out when he removed the bark and outer layer of tissue around a tree trunk. After several weeks, the tree died. The plant has a transport system vessels, which should distribute water and carry nutrients up and down a plant. These vessels are known as transport or vascular tissues in plants. **Two types of vascular tissues:** Xylem and Phloem. ## Xylem * has two functions: conduct water and dissolve mineral salts from the roots to the stems and leaves, and provide mechanical support within the plant. * **TRACHEID** - xylem cell found in all vascular plants * **VESSELS** - xylem cell found in flowering plants. **Three theories that explain the transport mechanism among plants:** 1. **ROOT PRESSURE** - suggest that cells in roots actively pump water or ions into the xylem tissue, causing a change in the concentration gradient, so water moves to the xylem via osmosis. - Once water was build up in the xylem of the roots, it creates pressure that forces water to move upward, this process is known as **GUTTATION**. 2. **CAPILLARY ACTION** - is the ability of a substance to draw or stick another substance into it. - In plants, water rises on its own in a plant stem when it is in contact with another surface through the xylem tube. 3. **COHESION TENSION** - relies in the attraction between water molecules where water is pulled up from below. - this pull extends through the water in the xylem and draws water upward in the same way liquid is drawn up a drinking straw. ## Phloem * conducts manufactured food as well as hormones from the green parts of the plants, especially leaves, to the other parts of the plant. * **TRANSLOCATION** - process of transporting manufactured food through the phloem tissue. In full maturity, the wood in the center of a mature stem or trunk is called **HEARTWOOD**, which can no longer conduct water out rather functions only as a support.