1. Interactions Among Animal Systems (Part One)
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. Four functions that we will discuss in more detail are regulation, nutrient absorption, reproduction, and defense against injury and illness. This video will only cover regulation.

6. Regulation
Regulation – process of maintaining vital body conditions within an acceptable range in order to preserve homeostasis
Negative Feedback
Change is detected
Corrective response activated
Body condition returned to normal range
Corrective response switched off
Body condition leaves acceptable range
Regulation is the process of ensuring that vital body conditions remain within an acceptable range. The purpose of regulation is to maintain homeostasis, or stable internal conditions. Maintaining homeostasis is required for body systems to function properly.
Regulation occurs by a mechanism called negative feedback. The mechanism of negative feedback is outlined in the diagram shown. If a body condition strays from its acceptable range, a corrective response is activated. The corrective response returns the body condition to the acceptable range, and is then switched off. The cycle continues to ensure that homeostasis is maintained.
Homeostasis – stable internal conditions required for body systems to function

7. Negative Feedback Mechanism consists of three parts:
Receptors – sensors that monitor body conditions
Control center – brain interprets input from receptors and sends signals to effectors
Effectors – organs that respond to brain signals to return body conditions to acceptable range
A typical negative feedback mechanism consists of three parts. Receptors are sensors in the body that monitor various body conditions. Receptors send information to a control center, typically in the brain.
The control center interprets information from the sensors. If a body condition strays from its acceptable range, the control center sends a signal to effectors.
Effectors are organs that respond to signals from the control center by returning the body condition to its acceptable range.
Control Center
Receptors
Effectors

8. Regulation Regulated body conditions include: Body temperature
Heart and respiration rates
Molecule concentrations in blood
Regulated body conditions include body temperature, heart and respiration rates, and molecule concentrations in the blood. Let’s look at how and why each of these conditions are regulated by an animal’s organ systems.

9. Body Temperature
Constant internal temperature required to maintain optimal function of cellular processes
Negative feedback loop:
Receptors in skin and brain monitor temperature
High temperature – brain signals sweat glands to cool body down
Low temperature – brain signals muscles to contract (shiver) to warm body up
A constant internal temperature is required to maintain the optimal function of cellular processes. Body temperature is regulated by a negative feedback loop.
Receptors in the skin and brain monitor external and internal temperatures. If the temperature becomes too high, the brain sends signals to glands in the skin to begin producing sweat. This cools the body down. If the temperature becomes too low, the brain sends signals to muscles to begin contracting, or shivering. This warms the body up.

10. Body Temperature Organ systems involved: System Functions
Integumentary
Skin contains temperature receptors & sweat glands
Muscular
Muscle contractions (shivering)
Nervous
Brain interprets input from temperature receptors and signals effectors to adjust body temperature
Three main organ systems interact to regulate body temperature. In the integumentary system, the skin contains temperature receptors and sweat glands. The muscles in the muscular system contract during shivering. In the nervous system, the brain interprets input from temperature receptors and sends signals to effectors to adjust body temperature.

11. Heart and Respiration Rates
Heart rate – number of times heart contracts per minute
Respiration rate – number of breaths per minute
Example: Exercise
Cells utilize oxygen faster
Blood pressure rises to meet increased oxygen demand
Heart and respiration rates increase
An animal’s heart rate is the number of times the heart contracts per minute. The respiration rate is the number of breaths the animal takes per minute. The body varies these rates based on variation in the oxygen needs of body cells.
An example of an activity that alters the oxygen needs of body cells is exercise. Cells use oxygen faster during exercise. This causes blood pressure to rise in order to speed the delivery of oxygenated blood to cells. Faster delivery of blood to the cells requires an increase in both heart and respiration rates.
Body varies these rates based on oxygen needs of body cells

12. Heart and Respiration Rates
Negative feedback loop:
Receptors in blood vessels and brain monitor blood pressure and oxygen levels in blood
High blood pressure – brain signals heart to decrease heart rate
Low blood pressure – brain signals heart to increase heart rate
High oxygen levels – brain signals lungs to decrease respiration rate
Low oxygen levels – brain signals lungs to increase respiration rate
Heart and respiration rates are regulated by a negative feedback loop. Receptors in blood vessels and the brain monitor blood pressure and blood oxygen levels.
If blood pressure becomes too high, the brain sends signals to the heart to decrease the heart rate. If blood pressure becomes too low, the brain sends signals to the heart to increase the heart rate. This negative feedback loop keeps the heart rate regulated.
Respiration rate is controlled in a similar fashion. If the oxygen levels are too high, the lungs are singled to decrease the respiration rate. If oxygen levels fall to low, the brain signals the lungs to increase the respiration rate.

13. Heart and Respiration Rates
Organ systems involved:
System
Functions
Circulatory
Heart varies heart rate according to signals from brain
Respiratory
Lungs vary respiration rate according to signals from brain
Nervous
Monitors blood pressure and oxygen levels
Sends signals to heart and lungs to adjust heart and respiration rates
Three main organ systems interact to regulate heart and respiration rates. In the circulatory system, the heart varies its heart rate according to signals received from the brain. In the respiratory system, the lungs vary their respiration rate according signals received from the brain. In the nervous system, the brain monitors blood pressure and oxygen levels and sends signals to the heart and lungs to adjust heart and respiration rates.

14. Molecule Concentrations in Blood
Body monitors molecule concentrations in blood to ensure appropriate delivery to and from cells
Utilizes hormones sent through blood
Regulated concentrations include:
Water balance
Blood sugar
An animal’s body monitors the concentration of various molecules in the blood. This is necessary to ensure that needed molecules are delivered to and from the body cell at the appropriate rate.
Two regulated concentrations in the blood are water balance and blood sugar. These concentrations are regulated using hormones sent through the bloodstream.

15. Molecule Concentrations in Blood
Negative feedback loop:
Receptors in endocrine glands monitor molecule concentrations in blood
Abnormal concentration – brain signals endocrine glands to increase or decrease hormone production
Change in blood hormone levels signals organs to adjust molecule levels in the blood
Molecule concentrations in the blood are monitored by negative feedback loops. Receptors in the endocrine glands monitor molecule concentration in the blood. If a concentration becomes abnormal, the brain signals the endocrine glands to increase or decrease production of regulatory hormones.
Hormones that are produced are added to the blood. A change in blood hormone levels signals effector organs to add needed molecules to or remove excess molecules from the blood.

16. Water Balance Regulated by hormone ADH Negative feedback loop:
Too little water – ADH level increases, signaling kidneys to remove less water from blood
Too much water – ADH level decreases, signaling kidneys to remove more water from blood
Excess water also excreted through skin (sweating)
Water balance in the blood is specifically regulated by a hormone called ADH in a negative feedback loop.
Too little water in the blood causes ADH production to increase. This hormone signals the kidneys to remove less water from the blood, increasing the amount of water in the blood.
Too much water in the blood causes ADH production to decrease. With less ADH, the kidneys remove more water from the blood, decreasing the amount of water in the blood. Excess water can also be excreted through the skin, by the process of sweating.

17. Blood Sugar Regulated by hormones glucagon and insulin
Glucagon – signals liver to add glucose to the blood
Insulin – signals liver, muscles, and fat cells to remove glucose from the blood
Negative feedback loop:
Low blood sugar – glucagon production increases and insulin production decreases, blood sugar rises
High blood sugar – insulin level increases and glucagon level decreases, blood sugar lowers
The amount of glucose, or sugar, in the blood is specifically regulated by the hormones glucagon and insulin. Glucagon signals the liver to add glucose to the blood. Insulin signals the liver, muscles, and fat cells to remove glucose from the blood.
If blood sugar is too low, glucagon production increases and insulin production decreases. This causes the liver to add more glucose and the liver, muscles, and fat cells to remove less glucose. The overall effect is a higher blood sugar.
If blood sugar is too high, glucagon production decreases and insulin production increases. This causes the liver to add less glucose and the liver, muscles, and fat cells to remove more glucose. The overall effect is a lower blood sugar.

18. Molecule Concentrations in Blood
Organ systems involved:
System
Functions
Endocrine
Hormone levels regulate molecule concentrations in blood
Nervous
Receives input from receptors
Signals endocrine glands to alter hormone production
Excretory
Kidneys remove excess water from blood
Integumentary
Skin contributes to water balance (sweating)
Digestive
Liver adjusts glucose level in blood to regulate blood sugar
Circulatory
Blood requires appropriate concentration of molecules
Blood transports hormones
Six main organ systems interact to regulate molecule concentrations in the blood. Regulatory hormones produced by the endocrine system signal effector organs to alter molecule concentrations in the blood. The nervous system receives input from receptors and sends signals to endocrine glands to alter hormone production. In the excretory system, the kidneys remove excess water from the blood. The skin of the integumentary system also helps remove excess water through sweat production. In the digestive system, the liver adjusts glucose levels in the blood. The blood of the circulatory system requires appropriate concentration of molecules and transports hormones to the effector organs.

19. 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.