Unit 3 Body Systems Topic 3 Endocrine System

Unit 3: Body Systems Topic 3: Endocrine System

Endocrine terms • Homeostasis: The condition of a stable internal environment in an organism • Endocrine system: One of the body’s major regulatory systems; includes glands that produce hormones • Hormone: “chemical messenger” that travels through the blood stream • Target cell: A cell with a receptor for a specific hormone (the cell that a hormone sends a signal to) • Endocrine gland: Ductless gland that produces and releases a hormone into blood

Glands of the Endocrine System • Hypothalamus o Part of the Brain - Not a gland o Links nervous and endocrine system • Pituitary gland o Connected to the hypothalamus o “Gland of glands” • Thyroid and Parathyroid o Metabolism, other. . • Adrenal glands o Fight or flight • Pancreas o Blood sugar • Gonads o Reproductive systems • Thymus o Immune system • Pineal Glands o Biological clock OBJ 10

Endocrine system function • Glands make hormones • Hormones diffuse into blood stream o Passive or active • Hormones have specific target cells OBJ 10

Hormone Signaling Pathways s Protein hormones s Bind to a receptor on cell membrane s Activate secondary messengers s Steroid hormones s Go through cell membrane s Bind to receptors INSIDE the cell OBJ 11

OBJ 12 Homeostasis: Blood Glucose Protein Hormones: Insulin and Glucagon

Homeostasis: Blood Calcium Obj 12 • Peptide Protein Hormones: • Parathyroid hormone (PTH) • Calcitonin

OBJ 18 Nervous vs. Chemical Regulation of Homeostasis Nervous System Mode of action Speed of action Duration of action Specificity Endocrine System Neurons and Glands and neurotransmitters hormones Quick Slow (in comparison to NS) Short Long (in comparison to NS) Targets specific organs Carried to all organs of the body, only acts on organs with specific receptors

Topic 4: Nervous System

Vertebrate Nervous System • Sense Organs • Collect stimulus • Ex. Eyes, Ears, Temperature sensors, pressure (touch) sensors • Motor organs (effectors) • Response • Ex. Muscles or glands OBJ 13

Seeing Receptors RODS

Hearing Receptors Cochlea

CNS vs. PNS OBJ 14

Central Nervous System • Brain o Cerebrum • Memory and senses o Cerebellum • Coordination of movements, voluntary muscles o Brain Stem • Controls involuntary muscles • Spinal cord o Transmits signals from the PNS to the brain, controls reflex's Brain stem Obj 14

Divisions of the Peripheral NS Controls internal environment Sensing organs Controls muscles Ex: eyes Ex: Blood Pressure

Autonomic Nervous System Rest and Digest Fight, Flight, Feed, Reproduce

OBJ 15 Neuron Structure Cell Dendrites Body – extension contains tentacle– like the extensions cell organelles the cell membrane, Axon Synaptic – long terminals tentacle of the likemembrane, cellofmembrane passes extensions, action collects “signals” from otherreleases neuronsneurotransmiters or sense organs, potential end of the action potential, generates the action potential (electrical signal)

What types of neurons exist? OBJ 15 s Sensory neuron s Receptor (in PNS) to CNS s Interneuron s Within CNS s Motor neuron Sensory neuron s CNS to effector (in PNS) Motor neuron

Reflex Arc • Programed stimulus response • Does not require the brain OBJ 14

OBJ 16 Action Potential (Nerve Impulses) • Electrical Signals travel from dendrite, to axon, to synaptic terminals Neuron at resting potential

Obj 16 Action Potential • Process of electrical signal moving through a neuron • AP’s produced by shifting ion concentrations along the axon • Involves: • Active transport • voltage gated facilitated diffusion of Na+ and K+

Action Potential movement along an axon

Neuron to neuron signaling: The Synapse • Synapse - Space between the synaptic terminal and the dendrites of adjoining neurons • Action potentials induce the release of neurotransmitters • Signaling molecules released via exocytosis • Generate an Action potential in the next neuron OBJ 17

OBJ 18 Nervous vs. Chemical Regulation of Homeostasis Nervous System Mode of action Speed of action Duration of action Specificity Endocrine System Neurons and Glands and neurotransmitters hormones Quick Slow Short Long Targets specific organs Carried to all organs of the body, only acts on organs with specific receptors