Respiratory System Recap

Gas Exchange Alveoli are tiny sacs that fill with air to allow diffusion of gas Many (millions of) alveoli provide a large total surface area for greater absorption A thin, single layer of flattened cells are on the wall of each alveolus to decrease the distance that gases need to diffuse across A dense network of capillaries (tiny blood vessels) surrounding the alveolus to remove CO2 from brought into from rest of body and to transport O2 to rest of the body Hemoglobin, the protein found in red blood cells, pick up O2 from the alveoli to transport to the rest of the body

Diffusion!? Whas dat? Diffusion: movement of molecules from an area of high concentration to an area of low concentration(i.e. with the concentration gradient); type of passive transport

INHALE our lungs fill with oxygen, which increases the concentration of O2 in alveoli, low concentration of O2 in capillaries capillaries contain a high concentration of CO2, low concentration of CO2 in alveoli Oxygen moves from the alveoli into the capillaries (high to low) and CO2 moves from the capillaries (high to low) into the alveoli and out your lungs which empty EXHALE

Nervous System

What is the Nervous System? The control system that enables animals to detect a stimulus and coordinate a response Stimulus: changes in the body that are detected by your body Response: your body’s reaction to this stimulus

How Does Communication Occur? Neurons Nerve cells are called neurons The functional unit of the nervous system Use electrical signals called impulses to communicate with other cells Nerve a bundle of neurons

Parts of A Neuron Dendrites Axon Myelin Sheath carry impulses from outside the cell into the cell body Axon carries the impulse away from the cell body towards neighbouring cells - conducting wire Myelin Sheath sometimes covers the axon, speeds up transmission of the nerve impulse Draw parts of neuron on the board

Parts of A Neuron Terminal knobs Neurotransmitters Synapse attach the neuron to other cells (other neurons or target cells) Neurotransmitters Chemical released by the terminal knobs that carries the impulse from 1 neuron to another Synapse connection between axon of one neuron and dendrites of an adjacent neuron Direction of impulse is always from the dendrites to the terminal knobs

Types of Neurons Sensory neurons Motor neurons Interneurons carry impulses from sensory receptors (eye, ear, nose, skin, tongue) to the brain Motor neurons carry impulses from the brain or spinal cord to muscles for movement or glands for hormone secretion Interneurons link the sensory and motor neurons in the brain and spinal cord

Parts of The Nervous system Central Nervous System Brain Spinal Cord

Parts of The Nervous System Peripheral Nervous System Somatic nerves (somatic nervous system) Voluntary Sensory Motor Autonomic Nerves (autonomic nervous system) Involuntary Sympathetic Parasympathetic

Somatic Nervous System Motor neurons under conscious control Voluntary control of body movements by the skeletal muscles All sensory neurons Sensory reception of external stimuli (touching, hearing, seeing, smelling, tasting)

Autonomic Nervous System Motor neurons that are unconsciously controlled Eg. Heart, body temp, blood pressure, pupil dilation, gland secretions Broken down into Sympathetic Prepares body for danger Parasympathetic Returns body to normal relaxed state after stress

Sympathetic and Parasympathetic Nerves Parasympathetic…think parachute

The Endocrine System

The Endocrine System The endocrine system sends messages to control and coordinate the body’s internal environment These messages are sent by chemicals that are called hormones, which are directly released into the bloodstream Similar to the nervous system, but uses hormones to deliver these messages rather than electrical impulses

Hormones chemical released into the bloodstream by one type of cell that has an effect on another type of cell in a different location help regulate and coordinate the functions of almost all organ systems important in maintaining a constant internal environment control many developmental changes

Glands Organ that manufactures and secretes hormones Pituitary gland and Hypothalamus control the hormone secretions of several other glands in the body Pituitary gland secretes the most hormones in the body The means by which these hormones are released into the bloodstream

Activity Sensory Receptors Pg 107 # 1-5 (Nelson Text) Homework Activity Sensory Receptors Pg 107 # 1-5 (Nelson Text)