Topic 5: Animal Systems Ch.22,23 Fig. 21.11 Nutrition Types p. 476 Herbivore Organism that eats plants. Carnivore Organism that consumes meat. Omnivore Organism that eats both plants and animals. Food Processing p.476 Food processing consists of 4 main stages 1. Ingestion Eating. 2. Digestion - Breaking food down into molecules small enough for the body to absorb. 3. Absorption - Uptake of monomers from the digestive compartment (gut). 4. Elimination - Undigested material passes out of the gut. Fig. 22.1 Fig. 22.5 Human Digestive System pp.479-484 Our digestive system is basically a tube through our body, with some exocrine glands. It consists of: 1. Mouth Ingests food. 2. Esophagus Connects the Mouth and stomach. 3. Stomach Stores food and Uses acids, enzymes and Muscle contractions to aid in digestion. Human Digestive System 4. Small Intestine Long tube that does most of the digestion (with enzymes) and absorption. 5. Liver Produces bile salts (store in the gall bladder) that are emptied into the small intestine to help break down fat. 6. Pancreas Produces a juice that is emptied into the small intestine that neutralizes stomach acid and contains enzymes. 7. Large intestine Reabsorbs water and minerals and compacts undigested food. 8. Rectum Where feces is stored until it is passed out the anus. 1
Other Digestive Systems - Some organisms have digestive systems very similar to humans. E.g. pigs. - Others have structures that are modified for special diets: 1. Rabbits have longer digestive tracts to help digest plants. 2. Cows have a larger stomach that is home to special bacteria that help them break down cellulose in plant cell walls. 3. Jellyfish have only one opening to their digestive tract. Food enters, is digested, and then waste pass out the same opening. Eating Healthy pp.489-491 Malnutrition The result of not eating the correct amount of nutritious food. It includes: 1. Undernutrition A diet that does not contain enough nutritious food. - This can result from metabolic or digestive problems, a diet that contains mainly one food, or anorexia and bulimia. 2. Obesity Being overweight. Often the result of eating too much food high in fat and sugar. Circulatory System pp.496-506 For large animals diffusion and osmosis is too slow to effectively move materials into and out of the body. A circulatory system is therefore used to transport, exchange, load and unload materials. E.g. oxygen, nutrients There are three basic parts: 1. Heart 2. Blood Fig. 23.18 3. Blood vessels Circulatory System Some animals do not have interconnected blood vessels: Open circulatory system A heart pumps blood in its coelom through open ended tubes and it then flows out among cells. E.g. Insects. Fig. 23.1 Circulatory System Closed circulatory system A heart pumps blood inside of closed vessels. Blood stays inside the vessels and exchange happens across their wall. Generally closed circulatory systems allow for a more active lifestyle. E.g. Humans. Fig. 23.1 Circulatory System Humans have a closed circulatory system with a central heart. The heart has four chambers: - Left ventricle Pumps blood around the body. - Right atrium Collects blood from the body. - Right ventricle Pumps blood to the lungs. - Left atrium Collects blood from the lungs. 2
Fig. 23.4 Circulatory System There are three types of blood vessels: Arteries Carry blood away from the heart. Generally this blood contains oxygen. Veins Carry blood towards the heart. Generally this blood contains carbon dioxide. Capillaries Smallest vessels that connect arteries and veins. All material exchange happens across the walls of capillaries. Fig. 23.7 Circulatory System Fig. 23.10 Blood has four components: Red blood cells (rbc) Contain hemoglobin, a protein that carries oxygen or carbon dioxide. White blood cells (leucocytes) Involved with the immune system. Platelets Pieces of cells that aid in blood clotting. Plasma Liquid that helps cells flow through the blood vessels and carries some carbon dioxide. Fig. 23.12 3
Respiratory System pp.507-513 To make ATP animals perform cellular respiration. Cellular respiration requires oxygen and produces carbon dioxide. p.507 Respiratory System pp.507-513 Gases are moved around the body by the circulatory system and exchanged with the environment by respiratory surfaces. These surfaces must be large to take in lots of oxygen and remove carbon dioxide. There are four major types of respiratory surfaces: Respiratory System 1. Skin If the organism is small, has a large surface area, and has moist skin, gases can be exchanged across it. E.g. Earthworm, planarian Fig. 23.15 Respiratory System 2. Gills Branched structures that exchange gases in aquatic environments. E.g. Fish, some amphibians Fig. 23.15 Respiratory System 3. Lungs Internal highly branched organs with moist surfaces for gas exchange. They can be expanded to pull air in and contracted to push air out. E.g. Mammals, birds. Respiratory System 4. Tracheae Highly branched internal tubes that deliver oxygen right to internal organs. This is a very efficient mechanism for small organisms. E.g. Insects. Fig. 23.15 Fig. 23.15 4
Respiratory System Fig. 23.19 Humans have two lungs in an air-tight chamber in the chest (thorax). Air enters through the mouth or nose, through the pharynx into the larynx into the trachea. The trachea branches into bronchioles. At the end of the bronchioles are small sacs called alveoli, which are the site of gas exchange. The Immune System pp.518-527 The body has two lines of defense against things that will make us sick (pathogens). 1. Non Specific Response - Attacks all pathogens the same way. - Includes external structures like the skin, mucus and wax which prevent pathogens from entering cells. - If the pathogen gets in, the inflammatory response sends blood to the area which includes white blood cells called macrophages. -Macrophages eat and digest the pathogens. Fig. 24.4 The Immune System 2. Immune System (Specific Response) A) Humoral Immunity - Helper T cells find and bind to pieces of pathogens (antigens) and activate B cells. - B cells divide and produce antibodies. - Antibody Y shaped proteins that stick to specific antigens. - Binding to antigens on pathogens may cause the antigen to become harmless or be easier to be ingested by macrophages. Fig. 24.7 5
The Immune System B) Cell-Mediated Response - Helper T cells find and bind to antigens and activate Cytotoxic T cells. - The cytotoxic T cells look for cells with that specific antigen and kill it. Immune System (Specific Response) Fig. 24.12 After the infection is eliminated, memory cells are made. Memory cells - Copies of the B and T cells for a specific pathogen that remain in the body to fight off the next infection. The Immune System The cells involved with the immune system are mostly located inside the lymphatic system. Lymphatic system System made of vessels (tubes) and nodes (small circular organs) that carry lymph (fluid) filled with white blood cells throughout the body. Endocrine System pp.536-539 Endocrine system Regulates control of bodily functions (homeostasis) using hormones. Hormone Chemical that that cause important changes within the body. The endocrine system regulates the body similar to the nervous system, but is slower and generally is used for processes that take more time. I.e. growth and development. Fig. 24.5 Fig. 25.4 Endocrine System - Hormones are made in special organs called glands that are scattered throughout the body. -Hormones are then released into the blood and travel throughout the body, but affect only specific target organs. E.g. The thyroid gland is located in the neck. It secretes the hormone thyroxine which controls metabolism. E.g. The adrenal glands are located above the kidneys and secrete epinephrine (adrenaline) which turns on the fight or flight response. 6
Nervous System pp.576-577,581-582,587-593 Nervous system - Regulates control of bodily functions (homeostasis) using neurons. Neurons (nerve cells) Cells that send electrical signals quickly throughout the body. The nervous system is closely linked to the endocrine system, but is much faster, and generally is used for processes that require immediate action. I.e. removing your had from a hot stove. Also, signals are sent only to a specific effector. Fig. 27.2 Fig. 27. 7 Nervous System Our nervous system is divided into: 1. Central nervous system (CNS) Brain and spinal cord. 2. Peripheral nervous system (PNS) All other nerves. - Radially symmetrical animals have a nerve net that is spread throughout the animal. There is no brain. - Other bilaterally symmetrical animals have a concentration of neurons in the head region but are as complex as the human brain. Nervous System Neurons are divided into three categories based on function: 1. Sensory neurons Receive information from the environment (from the receptor). 2. Interneurons Process information and decide what to do. 3. Motor neurons Send signals to muscles or other organs (to the effector). Nervous System - There are five types of sensory receptors: 1. Pain receptor Senses pain. I.e. pain receptors detect if your skin is cut. 2. Thermoreceptor Senses changes in the temperature. I.e. thermoreceptors in your skin detect when it is cold. Fig. 27.17 7
Nervous System 3. Mechanoreceptor Sense movement or pressure. I.e. Different mechanoreceptors in the skin can detect a light touch or strong pressure. Fig. 27.17 Nervous System 4. Chemoreceptors Sense the presence of specific chemicals. I.e. Chemorecptors on your tongue detect sodium, sugar, acids or bases. 5. Electromagnetic receptors Sense changes in the electromagnetic spectrum. I.e. Electromagnetic receptors in your eye detect light. Fig. 27.19 Fig. 27.21 Reproductive System pp.552-558, Animal reproduction can be done asexually or sexually. Asexual reproduction involves one parent, with the offspring budding off, growing from a fragment, or developing from an unfertilized egg. Sexual reproduction involves a male producing sperm and a female producing eggs. Fertilization can be internal or external. Reproductive System pp.552-558, Humans only reproduce sexually with internal fertilization. Males possess two testes in which sperm develop. Sperm then enter the epididymis where they mature. During ejaculation, sperm leave the epididymis, enter the vas deferens and exit through the urethra of the penis. Reproductive System pp.552-558, Semen is released by ejaculation and contains sperm along fluid from the seminal vesicles and prostate gland. Fig. 26.5 8
Reproductive System pp.552-558, Females have two ovaries which contain follicles which contain developing eggs. When the egg is mature the follicle bursts and the egg enters the oviduct (fallopian tube). The oviducts connect to the uterus where embryos develop. The cervix is the connecting point between the uterus and vagina. Fig. 26.6 Reproductive System pp.552-558, Fertilization happens in the oviduct. The zygote undergoes cleavage (division) to form a blastula (early embryo). The blastula travels to the uterus and implants in the lining (endometrium). The endometrium and outside of the embryo form the placenta, the organ that exchanges materials between the mother and embryo. The placenta is connected to the embryo by the umbilical cord. Fig. 26.15 Fig. 26.16 Reproductive System pp.552-558, Development is divided into thee phases: 1. First Trimester 0 to 3 months. The embryo goes from one cell to developing most systems. 2. Second Trimester 3 to 6 months. The systems are developed and refined more. 3. Third Trimester 6 to 9 months. Most growth occurs here. 9
Fig. 26.17 Skeletal System pp.594-595 The skeleton provides support, protection, and allows for movement. Our skeleton is divided into two sections: 1. Axial Centrally located for support. It includes the skull, spinal column and ribs. 2. Appendicular Bones of the limbs used for movement. Fig. 27.26 Skeletal System Bones in the skeleton are connected by three types of joints: 1. Ball and socket Used for rotating in shoulders and hips. 2. Hinge Used for bending in one direction in knees and elbows. 3. Pivot Used to rotate bones relative to each other in the forearm. Fig. 27.26 Muscle System pp.596-598 Movement of the skeleton requires coordination with the skeletal muscles. Muscles can only pull (contract) they can not push bones. Therefore they are always found in pairs. I.e. one to raise an arm up and one to lower it down. Muscles are connected to bones by connective tissue called tendons which do not contract. Fig. 27.30 Excretory System pp.468-470 Terrestrial and marine animals are constantly loosing water to dry or hypertonic environments. If they live in fresh water (hypotonic), water is constantly entering the body. Either situation could result in death so two strategies have evolved to deal with this problem: 1. Osmoconformers Organisms that have the same solute concentrations (Isotonic) as their environment so they don t have to regulate their amount of water. E.g. Jellyfish. Excretory System 2. Osmoregulators Organisms are have different solute concentrations (hypotonic or hypertonic) as their environment so they must constantly move water in or out. E.g. Humans. - In humans osmoregulation is done by the kidneys. - The kidneys also eliminate metabolic waste in the form of urea. - Cells throughout the body constantly make poisonous ammonia. - This is converted to the less toxic urea and diffuses to the blood. 10
Excretory System - The blood also removes any excess water in cells or provides water to cells that don t have enough. - Blood is then filtered by nephrons in the kidneys. - Nephrons take most of the plasma and dissolved materials from the blood. - Water and needed materials are then selectively added back to the blood. Excretory System - What is left in the nephron enters a collecting duct, out of the kidney into the ureter, to the urinary bladder, then out the body through the urethra. 21.17 11