Unit 3 Biological Bases of Behavior

The Nervous and Endocrine Systems Module 10 Learning Targets 10-1 Describe the functions of the nervous system’s main divisions, and identify the three main types of neurons. The Nervous and Endocrine Systems 10-2 Describe the nature and functions of the endocrine system and its interaction with the nervous system.

What is the nervous system? the body’s speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems

What are nerves? bundled axons of many neurons that form neural cables connecting the central nervous system with muscles, glands, and sense organs. For example, the optic nerve bundles a million axons into a single cable carrying the messages from the eye to the brain

What are the three types of neurons? There are three types of neurons: sensory (afferent), motor(efferent) and interneurons.

How are sensory and motor neurons different? sensory neurons motor neurons contain afferent nerve fibers carry information from the sense organs to the CNS contain efferent neurons carry messages from the CNS to the muscles and glands

How is the nervous system divided?

Your turn! Work with a partner to correctly label the divisions of the nervous system.

What is the Central Nervous System (CNS) and what does it do? The CNS is made up of the brain and spinal cord. The CNS is the decision maker… it is responsible for coordinating incoming sensory messages and outgoing motor messages.

What is the Peripheral Nervous System (PNS) and what does it do? The PNS is made up of sensory and motor neurons. The PNS connects the body to the CNS by gathering information from the senses and transmitting messages from the CNS.

What are the two parts of the peripheral nervous system? somatic autonomic controls the body’s skeletal muscles also called the skeletal nervous system controls the glands and the muscles of the internal organs (such as the heart) operates automatically

1. What Would You Answer? 1. What Would You Answer? Which division of the peripheral nervous system enables a person to move the muscles necessary to walk down the street? central nervous system B. sympathetic C. parasympathetic D. somatic endocrine

How is the autonomic division further broken down? sympathetic nervous system parasympathetic nervous system arouses the body, mobilizing its energy fight, flight or freeze The gas pedal of a car. calms the body, conserving its energy rest or digest The brake pedal of a car.

The sympathetic nervous system… accelerates heartbeat, raise blood pressure, slows digestion, raises blood sugar, and cools the body

The parasympathetic nervous system… decelerates heartbeat, lowers blood pressure, stimulates digestion, processes waste, and calms the body

AP® Exam Tip Understanding the physiological effects of stimulation by the sympathetic and parasympathetic divisions is often assessed on the AP® exam. Pay close attention to the diagram in the previous slide and spend time learning the mechanisms that are stimulated or depressed during activation.

2. What Would You Answer? 2. What Would You Answer? Which division of the autonomic nervous system calms a person down once a stressful event has passed? parasympathetic B. central C. somatic D. sympathetic endocrine

How do the two parts of the central nervous system function? brain spinal cord Comprised of the cortex and subcortical structures carrying out various functions Nerves arranged into neural networks Like people grouping in cities 2-way connection between PNS and brain Oversees the sensory and motor pathways of reflexes.

How does a reflex occur? 1 Sense receptors in the skin send signals up through the spinal cord via sensory (afferent) neurons. 2 Interneurons in the spinal cord receive the information from the sensory neurons and send signals back through motor neurons. 3 Motor (efferent) neurons connect to muscles in the body and direct movement.

How does a simple reflex occur? A simple reflex ... like that to pain… occurs only in the spinal cord before information reaches the brain.

What is the endocrine system? the body’s “slow” chemical communication system; a set of glands that secrete hormones into the bloodstream

What is the difference between the nervous system and the endocrine system? Neurons release neurotransmitters Neurotransmitters move across synapses Neural transmission is nano-fast “text message” Glands secrete hormones Hormones move through the bloodstream Hormonal secretion is slower “email”

Hormones are _____ released into the bloodstream. 3. What Would You Answer? 3. What Would You Answer? Hormones are _____ released into the bloodstream. neurons B. myelin C. action potentials D. electrical messengers chemical messengers

What are the glands of the endocrine system?

What are the adrenal glands? When the sympathetic nervous system is activated (during a fight, flight, or freeze event), the adrenal glands release epinephrine and norepinephrine (adrenaline and noradrenaline) to energize the body.

Fun fact! Norepinephrine (noradrenaline) is both a hormone and a neurotransmitter. Epinephrine (adrenaline) energizes the body, but norepinephrine (noradrenaline) is released in the PNS to calm the body.

What is the pituitary gland? The pituitary gland is the endocrine system’s most influential gland. The hypothalamus directs the pituitary gland to regulate growth and control other endocrine glands. The hypothalamus is part of both the CNS and the endocrine system.

The pituitary gland and its secretions. growth hormone: regulates growth and metabolism Oxytocin: stimulates the uterine contractions of childbirth and milk secretion during breastfeeding; also promotes pair bonding, group cohesion and trust. Pituitary gland secretions direct other endocrine glands to secrete their hormones.

Learning Target 10-1 Review Describe the functions of the nervous system’s main divisions, and identify the three main types of neurons CNS is the brain and spinal cord PNS is divided into the somatic and autonomic systems the sympathetic and parasympathetic are the divisions of the PNS Three types of neurons: sensory, motor and interneurons

Learning Target 10-2 Review Describe the nature and functions of the endocrine system and its interaction with the nervous system. The endocrine system secretes hormones into the bloodstream The adrenal glands release hormones that trigger the fight, flight or freeze response The pituitary is the master gland and is influenced by the hypothalamus