1. Interactions Among Animal Systems (Part Two)
Biology 10(A)

2. Interactions Among Animal Systems
Learning Objectives
Identify major organ systems in animals
Describe the interactions that occur among systems to carry out vital animal functions
After this lesson you will be able to identify major organ systems in animals. You will also be able to describe the interactions that occur among these systems to carry out vital animal functions.

3. Levels of Organization
An organism consists of several levels of organization
Organism
Organ Systems
Organs
Tissues
Cells
A multicellular organism is made up of several levels of biological organization. The smallest unit of life is a cell. A group of similar cells make up a tissue. A group of tissues that work together to perform a common function make up an organ. A group of organs working together make up an organ system. All of the organ systems make up a complete organism.

4. Animal Systems Eleven major organ systems: System Function(s) Skeletal
Structural support
Muscular
Movement
Integumentary (skin)
Barrier from external environment
Circulatory/Cardiovascular
Transport molecules throughout body
Respiratory
Exchange carbon dioxide & oxygen
Digestive
Break down food molecules
Excretory/Urinary
Remove waste products from blood
Immune
Destroy pathogens that enter body
Nervous
Send regulatory messages throughout body
Endocrine
Produce hormones that regulate vital processes
Reproductive
Production of sex cells & offspring
There are eleven major organ systems in an animal. Each system is designed to carry out a specific function necessary for the survival of the animal.
The skeletal system provides support and the muscular system works with the skeletal system to provide movement. The integumentary system, or skin, forms a barrier from the external environment. The circulatory system uses blood to transport needed molecules throughout the body. The respiratory system provides the body with oxygen and removes carbon dioxide. The digestive system breaks down food molecules for the body to use. The excretory system removes waste products from the blood. The immune system kills pathogens, or disease-causing agents, that enter the body. The nervous system sends regulatory messages throughout the body. The endocrine system produces hormones that help regulate vital processes. The reproductive system is responsible for the production of sex cells (egg and sperm) and offspring.

5. Interactions Among Animal Systems
Organ systems interact to carry out vital functions
Examples:
Regulation
Nutrient absorption
Reproduction
Defense against injury and illness
While each system has its own unique functions, all organ systems interact to carry out many functions that are vital to an animal’s survival. This video will detail nutrient absorption, reproduction, and defense against injury and illness.

6. Nutrient Absorption
Nutrient absorption – passage of broken down food molecules through intestinal walls into bloodstream to be delivered to body cells
Nutrient absorption is the passage of broken down food molecules through the walls of the small intestine. The purpose of nutrient absorption is to deposit nutrient molecules into the bloodstream to be delivered to body cells. Body cells require a steady supply of nutrients to maintain cellular functions.
Nutrient absorption is composed of two processes: digestion and absorption.
Two processes:
Digestion
Absorption

7. Digestion
Digestion – break down of large food molecules into small nutrient molecules
Two types:
Mechanical
Chemical
Begins in mouth and continues through stomach and small intestine
Digestion is the process of breaking down large food molecules into smaller nutrient molecules. This process begins in the mouth and continues through the stomach and small intestine.
There are two types of digestion: mechanical and chemical.

8. Mechanical Digestion
Mechanical digestion – the physical break down of food into smaller particles
Examples:
Teeth & tongue chewing
Stomach muscles churning
Mechanical digestion is the physical break down of food into smaller particles. Chewing food using the teeth and tongue is one example of mechanical digestion. Another example is the churning of food by stomach muscles.

9. Chemical Digestion
Chemical digestion – reaction of digestive acids and enzymes chemically with food molecules to create smaller molecules
Examples:
Saliva in mouth
Gastric juices
Bile in small intestine
Chemical digestion is the reaction of digestive acids and enzymes with food molecules to create smaller molecules. Saliva in the mouth contains enzymes that work to chemically break down food. Gastric juices in the stomach and bile in the small intestine are also used in chemical digestion.

10. Absorption
Absorption – passage of small nutrient molecules into bloodstream
Occurs in small intestine
Small nutrient molecules pass through microvilli into blood vessels
Bloodstream carries nutrient molecules to rest of
body to
be used
by cells
Microvilli – small, finger-like
projections in intestinal wall
Lined with blood vessels
Absorption is the process of passing small nutrient molecules into the bloodstream. This process occurs in the small intestine. The walls of the small intestine are lined with microvilli. Microvilli are small, finger-like projections that are lined with blood vessels.
As nutrient molecules are broken down in the small intestine, they pass through the microvilli into the blood vessels. The bloodstream then carries the nutrient molecules to the rest of the body to be used by the cells.

11. Nutrient Absorption Organ systems involved: System Functions Digestive
Mouth, stomach, and small intestine digest large food molecules
Small intestine is site of absorption
Muscular
Muscle contractions push food through digestive tract
Muscle contractions in stomach aid mechanical digestion
Circulatory
Blood vessels absorb nutrients through intestinal walls
Blood transports absorbed nutrients to cells throughout body
Three main organ systems interact to carry out nutrient absorption in animals. The mouth, stomach, and small intestine of the digestive system all work to digest food molecules. The small intestine is the major site of nutrient absorption. Muscles of the muscular system contract to push food through the digestive tract. Muscle contractions in the stomach also contribute to mechanical digestion. In the circulatory system, blood vessels absorb nutrients through villi in the intestinal walls. The blood transports absorbed nutrient molecules to cells throughout the body.

12. Reproduction
Combination of male and female gametes to form a zygote that will develop into an offspring
Three processes:
Gamete production & storage
Fertilization
Development
Gametes – sex cells
Male – sperm
Female – eggs (ova)
Zygote – fertilized egg
In most animals, reproduction is the process of combining male and female gametes to form a zygote. The zygote then develops into a new organism, or offspring.
Gametes are sex cells. Male sex cells are called sperm. Female sex cells are called eggs, or ova. A zygote is a fertilized egg that results from the union of an egg and a sperm cell.
Reproduction consists of three distinct processes: gamete production and storage, fertilization, and development. The process of reproduction is necessary to ensure that the animal’s genes will be passed on, and the species will continue.
Egg
Zygote
Embryo
Sperm

13. Gamete Production & Storage
Male sperm are produced and stored in the testes
Female eggs are stored in the ovaries
All eggs are present at birth
Gamete production and storage is the first step in the reproductive process. Gamete production occurs within the male and female reproductive organs. Male sperm are produced and stored in the testes. Sperm mare produced throughout the male’s life. Female eggs are produced in the ovaries before birth, and are then stored there throughout the female’s life. Once a month, an egg cell is transformed into a mature ova and can be fertilized.

14. Fertilization
Fertilization – process of a sperm and egg cell (ovum) merging into a single cell
(zygote)
Male sperm:
Travel from testes through vas deferens and out the penis
Enter female through vagina, travel through cervix and uterus to fallopian tube
Female egg:
Travels from ovary into fallopian tube
Fertilization is the second step in the reproductive process. Fertilization occurs when a sperm and mature egg cell, an ovum, merge to form a single zygote cell. In some animals, including humans, fertilization occurs in the fallopian tube of the female reproductive system.
In order for fertilization to occur, a female egg cell must travel from the ovary into the fallopian tube. The male sperm must travel from the male to the female reproductive system to meet the egg in the fallopian tube. In the male, sperm travel from the testes, through a tube called the vas deferens, and out the penis. The sperm enter the female reproductive system through the vagina. The sperm then travel through the cervix and uterus to reach the egg in the fallopian tube.

15. Development Zygote travels into and implants in uterus
Fetus develops in uterus and exits through cervix and vagina
Ovum
Ovary
Zygote
Fallopian tube
Development is the third step in the reproductive process. Remember that in mammals, an ovum has left the ovaries.
It is fertilized in the fallopian tube and is now a zygote. This fertilized zygote travels from the fallopian tube to the uterus.
The zygote implants in the uterus and develops into an embryo.
As development continues, it is termed a fetus, or new organism. Once development is complete, the new organism exits the uterus through the cervix and vagina.
Embryo
Uterus
Fetus
Uterus

16. Reproduction Organ systems involved: System Functions Reproductive
Main site of reproductive processes
Endocrine
Hormones (testosterone, estrogen, progesterone, etc. ) regulate reproductive processes
Circulatory
Blood delivers hormones to reproductive system
Blood delivers nutrients to developing fetus
Three main organ systems interact to carry out reproduction in most animals. The male and female reproductive systems are the site of all reproductive processes. Hormones of the endocrine system, such as testosterone, estrogen, and progesterone, regulate reproductive processes. In the circulatory system, blood delivers the necessary hormones to the reproductive system. The blood also delivers nutrients to a fetus during development.

17. Defense Against Injury and Illness
Prevent and minimize damage to body tissues from environmental factors and pathogens
Animals have various defenses that are designed to protect them from injury and illness. The purpose of these defenses is to prevent and minimize damage to body tissues from environmental factors and pathogens.

18. Defense Against Injury
Skin and skeleton protect internal organs from environment
Examples:
Skull: brain
Rib cage: heart & lungs
Reflex actions – rapid, involuntary response to external stimulus (heat, pain, etc.)
Example:
Temperature receptors in skin detect heat & send signals to spinal column
Spinal column signals muscles to react to avoid a burn
Animals have two major defenses against injury. First, the skin and skeleton provide physical protection for internal organs. The skin acts as a barrier against entry by objects in the environment. The hardness of the skeleton protects vital organs. Examples are the skull providing protection for the brain and the rib cage providing protection for the heart and lungs.
The second major defense against injury is reflex action. A reflex is a rapid, involuntary muscular response to an external stimulus, such as heat or pain. Pulling away from a hot stove is an example of a reflex action. Tempe rature receptors in the skin detect the stove’s heat and send a signal to the spinal column. The spinal column signals the hand and arm muscles to pull away from the stove to avoid a burn.

19. Defense Against Injury
Organ systems involved:
System
Functions
Integumentary
Skin provides physical barrier to foreign objects
Skeletal
Skeleton protect internal organs
Muscular
Muscle reflexes allow quick reactions
Nervous
Sensory receptors detect changes in environment Brain sends signals to muscles
Three main organ systems interact to carry out injury defense in animals. The skin of the integumentary system provides a physical barrier to foreign objects from the environment. The skeleton protects internal organs. Muscle reflexes allow quick reactions when danger is sensed. In the nervous system, sensory receptors detect environmental changes and signal muscles to react.

20. Defense Against Illness
Pathogens – disease-causing agents
Examples: bacteria, viruses, parasites
Three levels of defense:
Barriers
Innate immune response
Adaptive immune response
Pathogens are disease-causing agents. Examples of pathogens include bacteria, viruses, and parasites.
Animals have three levels of defense against pathogens, each with increasing complexity. These three levels of defense are barriers, the innate immune response, and the adaptive immune response.

21. Barriers Barriers – physically block pathogens from entering body
Examples:
skin, hair, mucus, coughing, sneezing, stomach acids
Barriers are the first line of defense against illness. Barriers physically block pathogens from entering the body. Examples of barriers include skin, hair, mucus, coughing, sneezing, and stomach acids. Each functions to prevent illness from occurring.

22. Innate Immune Response
Innate response – rapid response to all pathogens in same generalized way
Response includes:
Inflammation
Phagocytes
Complement system
The second line of defense against illness is the innate immune response. If barriers do not effectively stop a pathogen from entering the body, the innate immune response takes over.
The innate response is a rapid response to all pathogens in the same generalized way. All pathogens exhibit some common chemical patterns. These chemical patterns trigger the innate immune response to occur. The innate response involves three major parts: inflammation, phagocytes, and the complement system.
Triggered by chemical patterns common to pathogens

23. Innate Immune Response
Inflammation – increased blood flow into affected tissue to deliver defensive molecules
Phagocytes – white blood cells that engulf and break down pathogens
Complement system – proteins coat pathogen’s surface to speed destruction by phagocytes
Inflammation is the result of increased blood flow into the infected tissue. The purpose of increased blood flow is to deliver defensive molecules to the site of the pathogen.
One type of defensive molecule delivered to the site of the pathogen is phagocytes. A phagocyte is a white blood cell that engulfs and breaks down pathogens.
Proteins are also delivered to the site of the pathogen as part of the complement system. These proteins coat the pathogen’s surface. This speeds up the destruction of the pathogen by phagocytes.

24. Adaptive Immune Response
Adaptive response – slower response dependent on recognition of specific pathogen
Response includes:
Antibodies
Lymphocytes
Pathogen
Antigen
Antibody
The third line of defense against illness is the adaptive immune response. If the innate immune response does not effectively destroy a pathogen, the adaptive immune response takes over.
The adaptive response is a slower response that depends on the recognition of specific pathogens. Each pathogen displays unique antigens on its surface. Recognition of these unique antigens triggers the adaptive immune response to occur. The adaptive response depends on the involvement of antibodies and lymphocytes.
Triggered by recognition of pathogen-specific antigens

25. Adaptive Immune Response
Lymphocytes – white blood cells, defend the body
B cells – make antibodies
Cytotoxic T cells – kill tagged pathogens
Helper T cells – direct attacks by others
Antibodies – bind to antigens on pathogens
A lymphocyte is a type of white blood cell that defends the body. There are specialized types of lymphocytes with definitive roles.
B cells produce antibodies.
Antibodies are proteins that recognize and bind to antigens on a pathogen’s surface.
Cytotoxic T cells can now kill the tagged pathogens. Helper T cells direct the attacks.

26. Immune Memory
Immune memory – phenomenon in which immune system is able to fight a previous infection more quickly
Lymphocyte cells continue to be produced after pathogen is destroyed
Allows for stronger response if same pathogen enters body again
The adaptive immune response leads to the development of a phenomenon called immune memory. In this phenomenon, the immune system is able to fight a previous infection more quickly than a new infection.
After a pathogen has been destroyed, the pathogen-specific lymphocytes continue to be produced as memory cells. Memory cells will easily recognize the same pathogen again. This allows for a stronger response the next time the pathogen enters the body, reducing the amount of time necessary to rid the body of the pathogen.

27. Defense Against Illness
Organ systems involved:
System
Functions
Integumentary
Skin, hair and mucus provide physical barriers to pathogens
Respiratory
Nasal mucus and hairs, coughing and sneezing provide physical barriers to pathogens
Digestive
Stomach acids kill pathogens in food molecules
Circulatory
Blood transports defensive molecules, white blood cells, and antibodies to site of pathogen
Immune
Phagocytes and lymphocytes attack and destroy pathogens
Adaptive response leads to immune memory
Five main organ systems interact to carry out illness defense in animals. In the integumentary system, skin, hair, and mucus provide physical barriers to pathogens. Nasal mucus and hairs, coughing, and sneezing in the respiratory system also act as physical barriers. Stomach acid in the digestive system is another example of a physical barrier to pathogens.
In the circulatory system, blood transports defensive molecules, white blood cells, and antibodies to the site of a pathogen. Phagocytes and lymphocytes of the immune system attack and destroy pathogens. The adaptive immune response also leads to immune memory.

28. Interactions Among Animal Systems
Learning Objectives
Identify major organ systems in animals
Describe the interactions that occur among systems to carry out vital animal functions
You should now be able to identify major organ systems in animals. You should also be able to describe the interactions that occur among these systems to carry out vital animal functions.