Copy everything in RED and draw/label when told to The Brain and Neurons Copy everything in RED and draw/label when told to

Levels of Organization (copy the pyramid) Organ systems are living things made of a group of organs that contribute to a specific function within the body. Organs are living things made of tissues that work together to perform a specific, complex function. Tissues are living things made of a group of cells with similar structures and functions. Cells are the smallest unit of life.

Types of Tissues Different tissue types work together within organs: Muscle tissue (most abundant): controls internal movements of materials (ex: blood, food) Epithelial tissue: closely packed cells covering the surface of the body and line internal organs (ex: inside chambers of heart, glands) Connective tissue: holds organs in place and binds different parts of the body together (ex: tendons, ligaments) Nervous tissue: receives messages from the body’s external and internal environments, analyzes the data, and directs response (ex: controls heart beat)

Figure 35-2 Human Organ Systems Part I Section 35-1 Nervous System Integumentary System Skeletal System Muscular System Circulatory System

Figure 35-2 Human Organ Systems Part 2 Section 35-1 Respiratory System Digestive System Excretory System Endocrine System Reproductive System Lymphatic System

11 Functions Nervous: coordinates the body’s response to change in the internal and external environments. Integumentary: serves as a barrier against infection and injury, helps to regulate body temperature, provides protection against UV radiation from the sun Respiratory: provides oxygen needed for cellular respiration and removes excess carbon dioxide from the body

Neurons Messages carried by the nervous system are electrical signals = impulses Nerve cells that transmit impulses = neurons Sensory neurons: carry impulses from sense organs to the spinal cord and brain Motor neurons: carry impulses from the brain and spinal cord to muscles and glands Interneurons: connect sensory and motor neurons and carry impulses between them

Parts of a Neuron Cell body = largest part containing nucleus and cytoplasm (most metabolic activity occur here) Dendrites = short, branched extensions spreading out from the cell body and they carry impulses from the environment or other neurons towards the cell body Axon = long fibers that carry impulses away from the cell body and ends at the axon terminal

DRAW and LABEL THIS A Neuron Section 35-2 Nucleus Axon terminals Myelin sheath Nodes Cell body Axon Nucleus Dendrites

Synapse At the end of the neuron, the impulse reaches an axon terminal where the impulse may be passed along to another neuron or another cell The location where a neuron can transfer an impulse to another cell = synapse The synapse is a small gap that separates the axon terminal from the dendrites of the next neuron or another cell The terminals contain tiny sacs or vesicles filled with neurotransmitters = chemicals used by a neuron to transmit an impulse across a synapse The impulse will continue with the stimulation exceeds the cell’s threshold

Dendrite of adjacent neuron Figure 35-8 The Synapse Section 35-2 Direction of Impulse Dendrite of adjacent neuron Axon Receptor Vesicle Axon terminal Synaptic cleft Neurotransmitter

Reaction activity Reaction time = the amount of time required for an impulse travel from your sensory neurons to your motor neurons

Brain and Spinal cord Both are protected by bone wrapped in 3 layers of connective tissue = meninges layers may have a space between them filled with cerebrospinal fluid which protects (shock absorber) and exchanges nutrients and waste

Brain About 100 billion neurons, mainly interneurons Major parts of the brain: Cerebrum Cerebellum Brain stem Thalamus Hypothalamus

DRAW THIS35-9 Cerebrum Thalamus Pineal gland Hypothalamus Cerebellum Section 35-3 Pons Pituitary gland Hypothalamus Cerebrum Medulla oblongata Spinal cord Cerebellum Pineal gland Thalamus