What is an Animal? Characteristics of All Animals 1. Animals are Multicellular 2. Animals are Eukaryotic 3. Animals are Heterotrophs 4. Animal cells lack cell walls

Evolutionary/Developmental Milestones in Animals 1.Cell specialization and levels of organization 2. Development of body symmetry and segmentation 3.Development of an internal body cavity and tissue layers

Levels of Organization

Body Segmentation Segmentation of the body allows development of various specialized limbs, such as antennae, pincers, walking legs, claws, wings, etc. Cephalization is the concentration of nervous tissues in one location which eventually produces a head region with sensory organs and a brain.

Tissue Layers & Body Cavity A body cavity, called a coelom, increases the efficiency of food intake and waste removal. Tissue LayerDevelops Into Endodermdigestion and respiration structures Mesodermmuscles, bones, blood, skin, reproductive organs Ectodermskin, brain, nervous system

ANIMAL BODY SYSTEMS Body systems are all interrelated and work together to perform their functions in animals. Body systems can be organized and studies by these functions:  REGULATION: Excretory & Nervous Systems  NUTRIENT ABSORPTION: Respiration, Digestion, & Circulatory Systems  DEFENSE: Immune, Integumentary, Lymphatic, Skeletal, & Muscular Systems  REPRODUCTION: Reproductive & Endocrine Systems

FACT OF THE DAY: * Messages travel along the nerves as electrical impulses. They travel at speeds up to 248 miles per hour!

Nervous System The nervous system maintains homeostasis (an internal stable environment) by controlling and regulating all other parts of the body. (short-term memory) REGULATION

Functions of the Nervous System 1.Sensory-uses receptors to gather information from all over the body 2. Interpretation-the brain then processes the information into possible responses 3. Response-sends messages back through the system of nerve cells to A.Control and coordinate functions throughout the body B.Respond to internal and external stimuli

Evolutionary Trends of the Nervous System Simple Complex

Structures of the Nervous System Neurons: the functional cell that transmits signals through the body; an individual nerve cell Parts of a Neuron 1.cell body- the largest part of the neuron; contains the nucleus and organelles 2. dendrites- short, branching extensions spreading out from the cell body; receive and carry impulses to the cell body 3. axon- long, fibrous part of neuron; conducts nerve impulses away from cell body

cell body muscle tissue TYPICAL MOTOR NEURON Axon dendrite synapse cell body

Because neurons never touch, chemical signalers called neurotransmitters must travel through the space called synapse between two neurons. Neurotransmitters Synapse (gap) The message is transferred when RECEPTORS receive neurotrans- mitters. (pink spheres)

Neuron Nerve Impulse- an electrical signal is sent from the dendrite, along the axon, to the terminal. A chemical message, called a neurotransmitter is released from the axon terminals into the synapse, where it travels to the next cell.

How Impulses Are Carried – Flow of Impulse: dendrite  nucleus  axon  jumps synapse  next dendrite

Types of Neurons a. sensory neurons- carry impulses from sense organs to brain/spinal cord (CNS) b. motor neurons- carry impulses from brain/ spinal cord (CNS) to muscles/ organs c. interneurons- carry impulses between sensory and motor neurons (within CNS)

Reflexes They are involuntary They happen very quickly Take place without the brain receiving the message They protect you by triggering an involuntary response to stimuli (stepping on a tack) Reflexes:

Divisions of the Nervous System Central Nervous System (CNS) Peripheral Nervous System (PNS)

Central Nervous System (CNS) A.Brain- “control center”- receives and analyzes information; processes and sends back instructions

Parts of the Brain 1. Cerebrum Controls muscles Jobs that are voluntary It stores messages Studying/thought Language judgment

Lobes of the cerebrum Reasoning, logic, language, etc. Processes sensory (taste/reading) impulses from the body Visual images/ vision Hearing, smell, memories

the Cerebrum

Language and Speech – strokes, tumors, injuries Broca’s Area: – Primary motor cortex in the frontal lobe that controls muscles – Damage to area means you can understand language but are unable to speak it Responsible for speech generation Ex – stroke patients (NY Med brocas area) 28:28- d section) Wernicke’s Area: – The posterior part of temporal lobe – Damage to area means you can speak but unable to comprehend speech Responsible for hearing speech /greys-anatomy-one-step- too-far Go to 21 min mark

Parts of the Brain 2. Cerebellum: controls involuntary functions of muscles & maintains balance and posture ( hand-eye coordination)

Parts of the Brain 3. Hypothalamus: Controls homeostasis in body * body temperature, water balance, hunger, thirst, biological clock, flight or fight response)

Parts of the Brain 4. Brain stem Controls involuntary functions Medulla Oblongata & Pons : *breathing, heart rate, blood pressure, swallowing, vomiting, digestion

Peripheral Nervous System (PNS) A.Consists of nerves –ropelike bundles of neurons outside of the CNS B.Gathers information, delivers it to and from CNS C. PNS divided into two systems: Somatic (voluntary) Autonomic (involuntary)

Autonomic Nervous System  Autonomic Nervous System - The involuntary branch of the nervous system  Divided into two divisions: 1.Sympathetic division 2.Parasympathetic division

Autonomic Functioning  Sympathetic – “Fight-or-flight”  Response to unusual stimulus  Takes over to increase activities  Increases heart rate, blood pressure, blood glucose levels, dilates the bronchioles of the lungs, and dilates the pupils  Remember as the “E” division = Exercise, excitement, emergency, and embarrassment

Autonomic Functioning  Sympathetic – “Fight-or-flight”  The effects of sympathetic nervous system activation continue for several minutes until its hormones are destroyed by the liver.  Helps explain why we need time to “calm down” after an extremely stressful situation.

Autonomic Functioning  Parasympathetic – Housekeeping activites  “Resting and digesting” system  Chiefly concerned with promoting normal digestion and elimination of feces and urine and with conserving body energy  Heart rate, blood pressure, and respiratory rates are at low normal levels; pupils are constricted; skin is warm; digestive tract is actively digesting food  Remember as the “D” division - Digestion, defecation, and diuresis (urination)

Levels of Organization Nerves Brain, spinal cord Nervous Neurons

Interaction with other systems for Regulation  Bones of the skeletal system protect the spinal cord and brain.  The brain controls heart rate, blood pressure, and breathing via the circulatory and respiratory systems.  Glands in the brain control the release of hormones of the endocrine and reproductive systems.  The brain controls muscles both in digestion and movement.

Diseases / Disorders of the Nervous System 1.Polio- a virus that attacks the spinal cord; eventually causes paralysis 2.Multiple Sclerosis (MS)- affects neurons; slows nerve impulses, causing muscle weakness, possibly paralysis. 3.Alzheimer’s- brain tissue deteriorates; severe memory loss 4.Stroke- a blockage in a blood vessel in the brain, causing brain damage 5.Concussion- a bruise to the brain when the brain hits the inside of the skull

Fun Facts A human body contains more nerve cells than there are stars in the Milky Way Neurons are the largest cell in the body and do NOT undergo mitosis Nerve impulses move at 100 meters per second or more Longest axon of a neuron is 15 ft! (in the giraffe)

Reticular Formation – neurons in the core of the brainstem (midbrain -arousal, pons & medulla-sleep) Sleep & wakefulness produces patterns of electrical activity in the brain Recorded as an ElectoEncephaloGram (EEG) Most dreaming during REM (rapid eye movement sleep)

Did You Know… Bottlenose Dolphins swim while sleeping, rising to the surface to breathe air regularly! – Their forebrain is divided into two halves. Since they sleep with one eye open and one closed they are able to sleep with one brain hemisphere at a time.

The amygdala is responsible for determining what memories are stored and where the memories are stored in the brain The hippocampus sends memories out to the appropriate part of the brain for long-term storage and retrieves them when necessary. Damage to this area of the brain may result in an inability to form new memories.

Lobotomy… Phineas Gage, 1848 – was a loving, caring father until the accident and then became detached, impatient & erratic Later in the 20 th century, surgical procedures were done to remove portions of the frontal lobe in attempt to cure severe behavioral and psychiatric behaviors