Digestion 1
What is the main job of the large intestine?
Water absorption
What results from vitamin C deficiency?
Scurvy
Complex animals have fluid transport systems for transporting nutrients, gasses, wastes, hormones, antibodies, etc. What is this transport system called?
Circulatory system
In what direction does most arteries carry blood in the body? What is the exception to this?
Arteries carry oxygenated blood away from the heart. The pulmonary arteries are the only arteries (in adults) that carry deoxygenated blood (goes to the lungs)
In the cardiac cycle, what are the two alternating stages?
Systole (contraction) and Diastole (relaxation)
What is the blind pouch called that is the first small part of the large intestine after the joining of the small intestine and large intestine?
Cecum
What is the definition of malnutrition?
A diet that lacks one or more essential nutrients or supplies less chemical energy than the body requires.
All vertebrates have a closed circulatory system (or cardiovascular system). What all is included in the closed circulatory system?
Blood, heart, and vessels
In what direction do most veins carry blood in the body? What is the exception to this?
Veins carry deoxygenated blood back to the heart. The pulmonary veins are the only veins that carry oxygenated blood (back to the heart).
What is the pacemaker of the heart and where is it located?
The sinoatrial (SA) node. It is located in the right atrium
What are animals called that cannot make organic molecules from inorganic sources and must eat other living things?
Heterotrophs
What happens in the body when an animal is undernourished?
When an animal is undernourished, it uses up stored fat and carbohydrates, and the body begins breaking down its own proteins for fuel. The body will begin breaking down its own muscles and the brain will become protein deficient.
Some animals don’t have a circulatory system. What is an example of an animal like this?
Cnidarians (jellyfish, etc.), or Platyhelminthes (flatworms), etc.)
Describe the fish heart and their circulatory system.
Fish have a 2 chambered heart (1 atrium and 1 ventricle). Blood is pumped from the ventricle to the capillaries of the gills. Gas exchange occurs in the gills, and then the blood goes to the arteries capillaries of organs veins atrium of heart. Fish have an O shaped single circuit
What are the valves that prevent backflow from the atria to ventricles. And what valves prevent backflow from ventricles to arteries.
Atria to ventricles - tricuspid and bicuspid valve
Ventricles to arteries - Semilunar valves
Describe water soluble vitamins and fat soluble vitamins and provide an example of each.
Water soluble vitamins are not stored in the body, and the excess is secreted (probably not harmless). Examples are vitamins C and B vitamins.
Fat soluble vitamins are stored in body fat and an excess can be toxic. Examples are vit A, vit D, Vit. E, Vit K.
What is the definition of essential nutrients? How many amino acids are essential in adult humans?
Essential nutrients are chemicals that animals require but cannot synthesize and therefore must get from their diet. In adult humans, there are 8 essential amino acids.
Some animals have an open circulatory system. This is when the animal has a heart, but the tissues are bathed in blood in an open cavity. What is an example of an animal like this? And what is the blood called in an open circulatory system?
Examples include Arthropoda (insects, etc.), and most Mollusca (snails, clams). The blood in an open circulatory system is called hemolymph.
Describe the amphibian heart and their circulatory system
Amphibians have a 3 chambered heart (2 atria and 1 ventricle - only one ventricle for pumping). There are now 2 circuits, which make an 8 shaped circuit - pulmonary circuit (lungs) and systemic (rest of the body). With a 3 chambered heart, there is still some mixing of oxygenated and deoxygenated blood
Describe a difference between arteries, veins, and capillaries.
Arteries are thicker than veins and veins are thin-walled and soft. Veins also have tiny valves to prevent back flow. Capillaries have only a endothelial layer which allows for exchange of chemicals by diffusion. Blood flow is slowest through capillaries for exchange and capillaries also have a large surface area for exchange.
The small intestine is highly adapted to maximize surface area for absorption. Describe some of the adaptions the SI has to increase surface area and what absorbs the nutrients from the small intestine (include the type of epithelium and its shape, and it’s adaptions).
The epithelium consists of a simple columnar epithelium. The inner walls are highly folded, and the folds are covered by villi(us), which also have microvilli. The epithelium of the Villus is also 1 cell thick, which make absorption easy. Within each villus are capillaries and a lymph vessel (lacteal), which both absorb nutrients.
Once the absorbed nutrients reach the liver, what does the liver do (what are some of its function)?
The liver stores or converts nutrient molecules into other molecules, modifies and regulates the nutrient mix before releasing materials back into the bloodstream, helps regulate the levels of glucose in the blood (regardless of what we ate), and it also removes toxic substances before the blood circulates broadly.
Describe the pathway of blood starting at the right atrium.
Answer: (1) Right atrium (receives deoxygenated blood coming from the body – vena cava) (2) Right ventricle (pumps deoxygenated blood to the lungs/pulmonary trunk) (3) Pulmonary trunk (goes to the lungs and branches into right and left pulmonary arteries) (4) Lungs (blood is oxygenated) (5) Pulmonary vein (goes back to the heart) (6) Left atrium (received blood coming from the lungs) (7) Left ventricle (pumps blood to the body) (8) Aorta (a big artery and distributes oxygenated blood to the body)
Describe the human heart (its location, what it consists of and is surrounded by, and the atria and ventricles).
The human heart is in the thoracic cavity and is protected by the ribs and sternum. It consists of cardiac muscle (myocardium) and is surrounded by a double layered sack (pericardium). The atria receive blood and are thin walled. The ventricles pump blood and are therefore thick walled and more muscular. The heart also has 4 valves to prevent back flow.
What are the 3 layers that make up arteries and veins? Briefly describe them
Outer – connective tissue with elastic fibers
Middle - smooth muscles and elastic fibers
Inner - endothelium (simple squamous epithelial tissue)