Unit 13 How the body helps keep our

Unit 13: How the body helps keep our body’s condition constant. 1

What is Regulation? • Definition - life process that helps keep conditions inside the body constant (homeostasis) • Regulation is accomplished using the Nervous System and the Endocrine System 2

Regulation Using The Nervous System NERVOUS SYSTEM Uses nerves to detect changes in the environment so the body can respond Composed of the Central Nervous System (CNS) and the Peripheral Nervous System (PNS) Uses neurons (nerve cells) 3

The Nervous System Central Nervous System Peripheral Nervous System • Consists of the brain and the spinal cord • Contains all other nerves that run through the legs and arms, which eventually connect to the spinal cord 4

The Nervous System - CNS The brain is divided into three main sections: - Cerebrum - Cerebellum - Medulla * Meningitis: When the membranes of the brain become inflamed 5

Brain Part Functions Cerebrum • Part of the brain responsible for thinking, reasoning, memory, etc. Cerebellum • Part of the brain that controls balance and coordination Medulla • Part of the brain that controls automatic functions such as breathing and your heart beat 6

The Brain Medulla Cerebrum Cerebellum 7

The CNS - The Brain and Spinal Cord • Attached at the base of the brain is the spinal cord • The spinal cord carries messages from the nerves in the body to the brain • Damage to the spinal cord can result in paralysis (loss of muscle control) Ex. Paraplegic (cannot walk) 8

Stimulus/Response • Stimulus: a change in the external environment that triggers an impulse – Detected by receptors of the five senses (touch, taste, hearing, sight, smell) • Response: the body’s reaction to a stimulus – Activated when the brain sends a message to the motor neuron which then activates the effector (muscle or gland) Ex. Bee sting (stimulus); swatting the bee away (response) 9

Reflexes • How we respond to a stimulus is our behaviors • Some behaviors are learned but others are reflexes (born with these behaviors) • The reflex arc is the path a reflex takes through the body. 10

Reflexes cont… • A reflex starts with the 1) receptor (recognizes the stimulus), goes to the 2) sensory neuron (sends signal to brain), to the 3) interneuron (routes the impulse to the correct part of the brain), to the 4) motor neuron (alerts the muscle), and then to the 5) effector (the muscle or gland) Ex. Touching hot stove 11

The PNS - Nerves of the Body • The Peripheral Nervous System is the network of branching nerves from the spinal cord into other parts of the body (Nerves outside the brain and spinal cord) • The peripheral nerves pick up stimuli from the environment and send it to the spinal cord and vice versa 12

PNS cont… 3 Types of neurons (nerve cells) sensory neurons interneurons - found in receptors; carry messages to spinal cord - relay signals in the brain/spinal cord from the sensory neuron to the motor neurons - carry messages from inside the brain/spinal cord back to parts of the body 13

The Neuron - scientific for “nerve cell” Dendrite Terminal branch Cyton Nucleus Axon Neurotransmitter 14

Parts of a Neuron Impulse Dendrite Cyton Terminal branch • An electrical or chemical message that is carried by a nerve cell • Receive impulses from other neurons • Contains nucleus • End of cell; sends impulses to next cell 15

Parts of a Neuron Synapse Neurotransmitter • Gap between neurons • Allow impulses to transfer between nerve cells Axon • Long fiber that carries impulse from cell body 16

Drugs of the Nervous System How do drugs impact our Nervous System? - slow us down; called depressants ex. Alcohol, Valium, morphine - speed us up; called stimulants ex. Caffeine, cocaine, nicotine 17

The Endocrine System 18

Regulation Using The Endocrine System ENDOCRINE SYSTEM Uses glands and the hormones they produce to regulate The glands release the hormones into the blood; called chemical regulation Slower responses than responses of the Nervous System 19

Endocrine Glands Gland/Location Hormone Function Pituitary (brain) Human Growth Hormone Controls growth and other glands; Master gland Thyroid (neck) *Parathyroid (also neck) Thyroxine *Parathyroid hormone Controls metabolic rate *Ca and Phosphorus use Adrenal (top of kidney) Adrenalin Increases heart and breathing rate; fight or flight Islet of Langerhans (Pancreas) Insulin Regulates sugar levels in blood Testes (male) Testosterone Controls sperm production and secondary sex characteristics Ovaries (female) Estrogen Controls egg production and secondary sex characteristics 20

Disruptions in Homeostasis GOITER - enlarged thyroid due to lack of iodine in diet - Iodine is found in fish and table salt 21

Disruptions in Homeostasis DIABETES - too little insulin released by the pancreas causing an increase in blood sugar - Can be regulated through diet and/or injections of insulin 22

Disruptions in Homeostasis GIANTISM - too much growth hormone - Andre the Giant suffered from giantism 23

Disruptions in Homeostasis DWARFISM - too little growth hormone produced - “Mini Me” in Austin Powers 24

Disruptions in Homeostasis Meningitis - inflammation of membranes (meninges) surrounding brain and spinal cord - bacterial or viral 25

RECAP: Regulation Review Regulation occurs using The Nervous System Uses electrical firings and neurons to regulate Fast The Endocrine System Uses hormones and glands to regulate Slower 26