The Nervous and Endocrine Systems…Communication…

The Nervous System How do we know when to eat? How do we know when to eat? How do we know if we are touching a hot stove? How do we know if we are touching a hot stove? How does our body control breathing, the heart beat, and all other functions without our thinking about them? How does our body control breathing, the heart beat, and all other functions without our thinking about them? The answer to all of these is the nervous system The answer to all of these is the nervous system

The Nervous System Our nervous system is how all of the parts of our body communicate with all of the other parts…its why we aren’t a bunch of separate parts doing their own thing…. Our nervous system is how all of the parts of our body communicate with all of the other parts…its why we aren’t a bunch of separate parts doing their own thing….

Neurons The cells in the nervous system are called neurons The cells in the nervous system are called neurons Neurons contain a cell body with a nucleus Neurons contain a cell body with a nucleus They also have dendrites (dozens) that receive signals either from other neurons or from the environment They also have dendrites (dozens) that receive signals either from other neurons or from the environment They have an axon (one) as well that sends the signal on to the next neuron (away from the cell body) They have an axon (one) as well that sends the signal on to the next neuron (away from the cell body)

A typical neuron

Nerve impulses A bundle of axons make up nerves A bundle of axons make up nerves Nerve impulses travel really quickly (250 miles per hour…400 km per hour) Nerve impulses travel really quickly (250 miles per hour…400 km per hour) When they get to the end of an axon they must cross the synapse…the gap between the neurons When they get to the end of an axon they must cross the synapse…the gap between the neurons They do this by causing chemicals (neurotransmitters) to be released that cross and create a new impulse at the other side They do this by causing chemicals (neurotransmitters) to be released that cross and create a new impulse at the other side

Structures of the nervous system Neurons are the smallest parts of the nervous system but they come together to form two parts Neurons are the smallest parts of the nervous system but they come together to form two parts The central nervous system The central nervous system The brain and spinal cord The brain and spinal cord The peripheral nervous system The peripheral nervous system The smaller nerves that send impulses to and from the organs (sensory neurons) and the muscles (motor neurons) The smaller nerves that send impulses to and from the organs (sensory neurons) and the muscles (motor neurons)

Questions… How is the nervous system involved How is the nervous system involved in controlling your digestion? in controlling your digestion? helping you play soccer? helping you play soccer? helping you read a book? helping you read a book? in controlling our heart rate? in controlling our heart rate?

The Endocrine System The endocrine system is another way that your body communicates with itself. The endocrine system is another way that your body communicates with itself. Instead of a nerve impulse, your body secretes hormones that regulate the activity of other cells. Instead of a nerve impulse, your body secretes hormones that regulate the activity of other cells.

Hormones Hormones are substances secreted by cells that regulate the activity of other cells Hormones are substances secreted by cells that regulate the activity of other cells The functions of hormones include: The functions of hormones include: Regulating growth, development, behavior, and reproduction Regulating growth, development, behavior, and reproduction Coordinating the production, use, and storage of energy Coordinating the production, use, and storage of energy Maintaining homeostasis (temperature, salt balance, metabolism, excretion) Maintaining homeostasis (temperature, salt balance, metabolism, excretion) Responding to stimuli from outside the body Responding to stimuli from outside the body

Examples: Have you ever had a “fight or flight” response? Have you ever had a “fight or flight” response? You see a snake? You see a snake? You are about to get caught cheating on a big test? You are about to get caught cheating on a big test? You know that killer zombies are after your brains? You know that killer zombies are after your brains? When you haven’t eaten in a while, how does your body control blood glucose levels? When you haven’t eaten in a while, how does your body control blood glucose levels? Glucagon and insulin tell the body to either store glucose and glycogen or to convert the glycogen back to glucose Glucagon and insulin tell the body to either store glucose and glycogen or to convert the glycogen back to glucose

Endocrine Glands Hormones are produced in the endocrine glands Hormones are produced in the endocrine glands These glands secrete hormones directly into the blood or the fluid around the cells These glands secrete hormones directly into the blood or the fluid around the cells The endocrine glands can act independently or together to help maintain homeostasis The endocrine glands can act independently or together to help maintain homeostasis The pituitary gland is the “master gland”- it secretes hormones that regulate all of your other glands. The pituitary gland is the “master gland”- it secretes hormones that regulate all of your other glands.

GlandsHormonesFunction Adrenal glandsaldosterone cortisol Maintains salt-and-water balance Regulates carbohydrates and protein metabolism Adrenal glandsepinephrine norepinephrine “fight or flight” response Ovariesestrogen progesterone Regulates female characteristics and Maintains growth of uterine lining PancreasGlucagon Insulin Stimulates the release of glucose Stimulates the absorption of glucose TestesAndrogens (testosterone) Regulates male characteristics

Relationships The nervous system and endocrine system both help regulate ALL of our body systems because they are how they communicate with each other! The nervous system and endocrine system both help regulate ALL of our body systems because they are how they communicate with each other!