Maintaining Homeostasis Nervous, Endocrine & Immune Systems

The Nervous System  A reaction to stimuli MAIN FUNCTIONS: Control and coordinate functions (ex. balance, breathing, heart rate, movement, etc. Respond to Stimuli

Regions of the human brain BRAIN STEM: involuntary actions (breathing, heart rate, etc.) CEREBELLUM: involuntary functions (balance and coordination) CEREBRUM- voluntary functions (senses, thoughts, emotions, speech)

How does the nervous system send its messages? It uses NEURONS!

Structure of a Neuron Myelin Sheath covers the axon and insulates it, increasing the speed that messages travel A bunch of neurons clustered together = Ganglion

Chemicals called Neurotransmitters are released into this synapse (space) so the message can be sent. These chemicals attach to receptors on the next neuron based on their shape and then can communicate their message Neurons line up to send messages throughout the body The space between the neurons is called a SYNAPSE

The Nervous System: Two Main Parts Central Brain Spinal Cord Peripheral Nervous System Sensory Nerves Motor Nerves Autonomic Nervous System Somatic Nervous

Peripheral Nervous System (PNS): We learned before about a stimulus and a response. Let’s take a closer look at exactly what happens in your body. Stimulus → Sensory Nerve → CNS → Motor Nerves → Response All impulses can only go in one direction…so why do we need 2 types of nerves?

Peripheral Nervous System (PNS): Stimulus → Sensory Nerve → CNS → Motor Nerves → Response Sensory Nerves = carry commands from sensory organs (such as skin) to the CNS

Peripheral Nervous System (PNS): Stimulus → Sensory Nerve → CNS → Motor Nerves → Response Motor Nerves = carry commands from CNS to muscles, other organs (such as glands) Autonomic Nervous System- Not in our conscious control (Digestion, breathing) Somatic Nervous System – In our conscious control (Walking)

Problems with the Nervous System Alzheimer’s-Deterioration of memory, personality, ability to function Causes: Genetic Mutations, Abnormal clumps and tangled bundles of fibers in brain Symptoms/Effects: Forgetfulness, loss of concentration, poor judgment, confusion Treatment: No cure or way to slow down. Can take some meds if caught early enough to help with cognition.

Problems with the Nervous System Multiple Sclerosis- nerve signals are slowed down or blocked Causes: destruction of myelin sheath Symptoms/Effects: depends on which nerves are affected- weakness on one side of the body, slurred speech, blurred vision, confusion Treatment: sometimes the symptoms disappear, usually come back; use meds and therapy to ease symptoms

Problems with the Nervous System Meningitis- inflammation of the membrane surrounding the brain and spinal cord Causes: bacterial or viral infection that gets into the brain Symptoms/Effects: high fever, severe headache, nausea, sudden changes in behavior/ can result in deafness, paralysis, mental retardation Treatment: depends on type- antiviral meds, antibiotics, other meds to treat symptoms, hospitalization

Endocrine System What is involved in the endocrine system? 1. Endocrine GLANDS- secrete (release) HORMONES into the blood 2. Hormones- chemicals that have a specific shape. Shape must match to the receptor to give the cell a message

What is the main function (job) of the Endocrine System? Release chemicals to send messages to other parts of the body Chemicals= Hormones Glands= Make and release hormones

Each gland makes a hormone that travels through the bloodstream to send a message by matching the shape of the receptor on a cell

Pituitary Thyroid Adrenal Pancreas Ovaries Testes

Pituitary Thyroid Metabolism Estrogen Testosterone Growth and protein synthesis Produce an egg Fill in open follicle Thyroid Metabolism -Helps glucose go into cells from bloodstream -Decreases the rate of glucose going into cells “Fight or Flight”: inc. heart rate, blood pressure, blood flow, breathing, release of glucose, sweating Estrogen Testosterone

Try the next few pages on your own or with a partner.

Disorders of the Endocrine System

Thyroid Gland Hormone: Thyroxin Overactivity (Too much hormone) Increased metabolic rate Increased food intake but loss of weight Hyperthyroidism (Grave’s disease) Goitre (swollen neck, maybe bulging eyes)

Goiter

Underactivity (Not enough hormone) Thyroid Gland Hormone: Thyroxin Underactivity (Not enough hormone) Hypothyroidism (Hashimoto’s disease) - Reduced metabolic rate Low food intake but gain of weight Myxoedema (when onset in adults) Cretinism (when onset in children) Can also cause a goitre

Myxoedema Puffiness (swelling) Fatigue Obesity Dry, thickened skin Mental impairment Thin, brittle hair

Cretinism Protuberant abdomen Short Stature Infertility Neurological impairment Constant Fatigue Obesity

Thyroid Gland Hormone: Calcitonin Overactivity Underactivity - Increased Bone Ca, decreased Blood Ca - Tetany (nerve problems leading to muscle spasms or cramps) Underactivity - Increase Blood Ca, decreased Bone Ca Osteoporosis (brittle bones) Kidney stones

Hormone: Parathormone (PTH) Underactivity Parathyroid Glands Hormone: Parathormone (PTH) Underactivity Low Blood calcium, High Bone Ca Tetany Overactivity High Blood calcium, Low Bone Ca Osteoporosis

Hormone: Insulin Overactivity Underactivity Pancreas Low blood sugar level ( ↓BSL) Hypoglycemia Underactivity High blood sugar level ( ↑BSL) Hyperglycemia Diabetes

Hormone: Glucagon Overactivity Underactivity Pancreas High blood sugar level ( ↑BSL) Diabetes Underactivity Low blood sugar level ( ↓BSL) Hyper insulinism

Anterior Pituitary Gland Hormone: Growth Hormone Overactive Giantism (children - very tall) Acromegaly (adults - bones & skin thicken) Underactive - Dwarfism (very short)

Giantism The man holding the baby in the photo is 8 ft, 2.5 inches tall

Acromegaly

Dwarfism Dwarfism occurs when there is short supply of GH in childhood. There are two types of dwarfism – Lorrain and Frohlich’s

Intermediate Pituitary Gland Hormone: MSH- Melanocyte Stimulating Hormone (causes color cells in skin to darken) Overactive Skin darkens Underactive Skin will not darken Albinism

albinism

Intermediate Pituitary Gland Hormone: LH, FSH, ICTH (sex hormones in males and females that aid in gamete production Overactive Unknown Underactive Sterility