Homeostasis and Body System Basics

The 2 benchmark areas for today: #1) B2.3A: Describe how cells function in a narrow range of physical conditions, such as temperature and pH (acidity) to perform life functions.   #2) B2.3d: Identify the general functions of the major systems of the human body (digestion, respiration, reproduction, circulation, excretion, protection from disease, and movement, control, and coordination) and describe ways that these systems interact with one another. Clarification: Systems described are limited to those involved in nutrition, cardiovascular and respiratory health.

Here They Are: Your Body Systems (Part 1). http://www.agen.ufl.edu/~chyn/age2062/lect/lect_19/147a.gif

And Your Body Systems (Part 2) http://www.agen.ufl.edu/~chyn/age2062/lect/lect_19/lect_19.htm

Homeostasis – the body’s response to a changing external environment to help maintain a stable internal environment

Examples: 1) Blood Sugar: in order to maintain a safe level our body uses insulin to reduce the amount of sugar in our blood and glucagon to increase it

2) pH: if pH levels are too high our body can produce a natural buffer (carbonic acid bicarbonate buffer) to help regulate it pH less than 7 = acidic pH is 7 = neutral pH more than 7 =alkaline

3) Temperature: is regulated by our brain through our skin Too Hot? Increase blood flow to extremities to cool the blood Widening of the blood vessels to increase flow to extremities and allow heat to escape Increase in perspiration(sweating) to increase evaporation on the skin

Too Cold? Decrease blood flow to extremities to help keep the vital organs warm Restriction of blood vessels to divert blood to deeper tissues so less heat escapes Increased cellular respiration to release more heat

Cardiovascular/Circulatory System – carries nutrients, oxygen, hormones and wastes through the body and distributes heat to help maintain homeostasis Made up off the heart, blood vessels and blood Like a chemical highway for the body

The Heart – pumps the blood throughout the body Arteries – blood vessels that carry blood away from the heart Veins – blood vessels that carry blood back to the heart Capillaries – tiny blood vessels where material is exchanged between the blood and surrounding fluid

Heart rate (pulse) – stretching of the blood vessels leading away from your heart, caused from the pressure of your blood being pushed out of the left ventricle (number pulses per minute is the heart rate)

Blood – interacts with EVERY body system by picking up and delivering products throughout the body (ie carbon dioxide, oxygen, waste) Plasma – the liquid portion of blood Red Blood Cells – doughnut shaped blood cells that transport oxygen White Blood Cells – destroys pathogens and helps the body develop immunities Platelets – pieces of cytoplasm from bone marrow that are used for clotting

http://youtu. be/PgI80Ue-AMo Now how do I remember this… http://youtu

Respiratory System - brings oxygen into to the body and carries carbon dioxide out of the body

Works closely with the circulatory system, exchanging gases between air and blood Helps to regulate blood pH Regulates blood oxygen and carbon dioxide levels

http://youtu.be/HiT621PrrO0

Digestive System – takes in food, breaks it down into molecules that the body can use, and gets rid of undigested molecules and waste

Mouth, esophagus and stomach begin the process of digestion by breaking food into small molecules Absorption of nutrients takes place in the small intestine primarily, aided by secretions from the liver and pancreas Components of food that are not digested leave the body as waste

http://youtu.be/Z7xKYNz9AS0

Excretory System – by removing toxic chemical, excretion enables the body to maintain its water and pH balance The kidneys filter wasters out of the blood and balance water levels Waste is removed through excretion of urine

Endocrine System – regulates metabolism (salt, water and nutrient balance in the blood), controls the body’s response to stress and regulated growth, development and reproduction

Endocrine glands and endocrine tissues produce and release hormones Hormones get moved throughout the body by the circulatory system

http://youtu.be/HrMi4GikWwQ

Nervous System – is a highly organized network of signaling cells called neurons Neurons – nerve cells that send electrical signals in order to communicate with each other and with muscles and glands

Two main divisions of the nervous system 1) Central Nervous System (CNS) - responds to internal and external information

2) Peripheral Nervous System (PNS) – contains sensory and motor nervous system and the rest of the body

A spinal reflex is an involuntary movement triggered by sensory input and produced by neural circulatory limited to the spinal cord

DiscoveryEducation – Investigating the Nervous System – Studying the Nervous System of Toads

What how might different body systems be involved in… Running a away from a bear Eating lunch with Ms. Pilarz Taking a test in Biology Getting poked by a sharp stick