Receives, processes, stores and transmits information from both inside and outside the body. It controls all of the activities of the body.The nervous system is made of:

The brain

The spinal cord

The nervesThe senses

• Nervous System– Central nervous system

• The brain: data processor• The spinal cord: transmission

channel (sometimes processor)

– Peripheral nervous system• The nerves (made up by a

collection of neurons): messenger.

The Neuron• A specialized nerve cell in the nervous system that

receives and transmits messages (nerve impulses).– Dendrites: receiver of the neuron– Cell body: contains the nucleus; transmits nerve impulse to

axon.– Axon: transmits nerve impulse to the axon terminals.– Axon terminals: transmission of nerve impulse via a liquid

to dendrite of another neuron. This transmission is called a synapse.

Nerve Impulses: Messages in the form of an electrical signal that is carried throughout the body by nerves.

A Neuron• Picks up stimuli and transform to nerve impulse.• Can be a conductor: transmitting nerve impulse to

another neuron

• Uses a lot of O2 and glucose for energy.

• Present for life• Cannot self-replicate or be replaced.• Human contains ~100 billion neurons

The nervous system also allows you to react to a stimulus.

A stimulus is a change in the environment that triggers a reaction. Example: A hot stove, hormones, sounds, light and electrical shocks

Automatic means that you do not have to think about your reactions. Example: If a bug flies by your eye, you will blink.

Neuron: Transmitting Nerve Impulses • A specialized nerve cell in the nervous

system that receives and transmits messages (nerve impulses).– DendritesDendrites: receives message and transforms

into nerve impulses.– Nerve impulses transmitted along axon to

axon terminals.– SynapseSynapse: Nerve impulse travels from one

neuron to another along neurotransmittersneurotransmitters (chemical substances) secreted by axon terminals.

– Transmission is complete when nerve impulse reaches its intended target. Ex: muscle

Transmitting Nerve Impulses

Peripheral Nervous System • Connects different parts

of the body to the central nervous system through nerve impulses.

• Main structure in system is a nerve.

• Nerve: a structure that helps transmit information between central nervous system and various parts of the body. Made up of axons of neurons

Two types of nerves: Sensory and Motor

• Sensory Receptor: specialized nerve cells that detect internal and external stimuli and transforms it into a nerve impulse. Ex: eye• Found throughout organism; prominent in sensory organs.

–Found elsewhere; capture info. from organ. Ex: receptor in muscle will receive info. for degree of muscle stretch.

• Sensory Nerves: transmit information as nerve impulses from sensory receptors to the CNS. Ex: optic nerve of eye

• Also picks up internal stimuli from vital organs.

The Motor Nerves• Transmit impulses from the CNS to the muscles

and glands in order to produce voluntary and involuntary movements. Ex: change in light from dark to light, affects size of pupil due to iris controlled by muscles.

the brain and the spinal cord.

It controls everything in the body.

* The Central Nervous System (CNS) controls all of the body’s activities.

* It is made of two main organs:

•An organ that controls your emotions, thoughts, and every movement you make.

•Protection:

•Located in the cranium (skull).

•Meninges: membrane surrounding brain and

spinal cord.•The brain is made of more than 10 billion nerves

•The brain communicates with the whole body using 12 pairs of nerves called cranial nerves.

* The Brain is a mass of nerve cells divided into three main parts…

1. The Cerebrum

2. The Cerebellum3. The Brain Stem

•The Cerebrum is the largest part of the brain. It is divided into the rightright (controls lefts side of body) and left hemispheres left hemispheres (controls right side of body). (p.209)

•It is the control center of voluntary movement, sensory interpretation and intelligence. It is also the center of emotions)• The cerebrum controls your thinking,

memory, speaking and it controls your movement and identifies the information gathered by your sense organs.

• Outer layer (grey matter) called cerebral cortex controls higher level thinking: planning, reasoning, logic.

* The cerebellum is below and to the back of the cerebrum.

1. The cerebellum controls your balance and movement coordination.

2. The cerebellum controls your posture by regulating the contraction of certain muscles.

* The Brain Stem connectsconnects the brain (cerebrum and cerebellum) to the spinal cord.

* 10 pairs of cranial nerves exit the stem.•It processes internal stimuli and the involuntary movement of the respiratory, digestive and circulatory system. The nerves in the brain stem control your heartbeat, breathing, and blood pressure.

*The spinal cord is the reflex centre.

* The spinal cord is the organ of the nervous system that carries information from body parts to the brain and vice versa. *31 pairs of nerves extend out•Spinal Nerves extend from the spinal cord to send nerve impulses to all parts of body.

•Spinal cord protected by meninges and bones of spinal column called vertebrae.

* The spinal cord is the reflex reflex centrecentre.

* A reflexreflex is rapid and involuntary, it happens quickly, in less than a second.

* An automatic, rapid, involuntary reaction to a stimulus (you don’t think about it). Brain only analyzes after event.

* Ex: removing hand from hot stove, or blinking in bright light.* Reflex Arc is the path taken by a nerve impulse during a reflex.

* The outer nervous system is made of the nerves and the sense

organs.

Ear

EyeSkin

Nerves Tongue

Nose

Sense organs carry messages about the environment to the central nervous system.

The environment is everything outside the body.

The sense organs gather information from outside the body, then send the messages to the brain.

The sense organs gather information (light, sound, heat, and pressure) from the environment.

VisionVision is your ability to see involving the eye and brain.The eyeeye is the sense organ for vision.The eye gathers light rays from light sources or reflected from objects and sends them to the brain.

Parts of the eye: sclera, choroid, retina, cornea, iris, lens, aqueous humour, vitreous humour.

Aqueous Aqueous humourhumour

Blind SpotBlind Spot

Iris

Pupil

• Crystalline LensCrystalline Lens: changes shape based on distance of object being looked at, to reflect image onto retina (converging lens). It accommodates.

• Nerve cells (cones and rodsNerve cells (cones and rods): photo-receptors convert light to nerve impulses– ConesCones: distinguish colours & RodsRods: variations of

light

• Nerve impulses sent to brain via optic nerve optic nerve where it gets processed and analyzed by the brain.

• Ear is the sensory organ for hearing.

• When a sound is made, the air around the sound vibrates producing waves.

• Hearing starts when some of the sound waves are picked up by the ear.

• Three sections:– Outer ear– Middle ear– Inner ear

1. Pinna (auricle)2. Auditory canal

3. Eardrum (Tympanic membrane)4. Ossicles: Anvil, Stirrup, Hammer

7. Cochlea

5. Eustachian tube

10. Auditory nerve

8.Semicircular canals9. Vestibule

The auditory canal is the tube between the pinna and the ear drum; carries sound vibrations. Lined with fine hairs and sebaceous glands (produce wax for protection)

The pinna (auricle) is the outer part of the ear; part you see. Designed to pick up sound waves.

Middle Ear

StirrupStirrup

AnvilAnvil

HammerHammer

Ossicles: The three smallest bones in the body: the hammer, the anvil, and the stirrup, move from the vibrations of the eardrum.The hammer gets the vibrations from the eardrum, then sends them to the anvil.The anvil passes the vibrations to the stirrup.The stirrup passes the vibrations to the inner ear.The Eustachian tube: connects middle ear to pharynx. It controls the amount of pressure on either side of the eardrum.

Semicircular Canals: fluid-filled canals in temporal bone; regulate balance when in motion. Connected to vestibular nerve.

Cochlea: fluid-filled structure lined with nerve cells; transforms vibrations into nerve impulses; connected to auditory nerve. The auditory nerve carries the nerve impulses to the cerebrum, brain analyzes and we hear sound.

Vestibule: liquid-filled structure; connects the semi-circular canals to the cochlea. Has a role in balance when stationary.

Inner EarInner EarVestibuleVestibule

Semi-circular canalsSemi-circular canals

1. Dead layer2. Living layer

7. Hair

3. Sensory receptors4. Blood vessels5. Sebaceous glands6. Sweat glands

8. Fat Cells

The skin is the sensory organ for touch. Largest organ covering entire

Entire surface of the body.

The nerves in the skin allow us to feel texture, pressure, heat,

cold, and pain.

Dead Layer: Outer layer of dead skin cells.Living Layer: Layer of cells undergoing mitosis; new cells push old cells to surface.

Sensory receptors: Structures that pick up stimuli: tactile sensations

(touch, pressure), thermal (heat, cold), painful (pain).

Blood vessels: nourish skin cellsSebaceious glands: Secretes sebum oily

substance waterproofs skin.Sweat glands: produce sweat.Hair:Partially covers epidermis, coming from dermis

Fat Cells: Layer of fat cells that act as thermal insulator and energy storage.

Structures that pick up stimuli: tactile sensations (touch, pressure), thermal (heat, cold), painful (pain).

• Functions as:– Sensory receptor– Protects internal organs and blocks invasion

of foreign bodies– Helps eliminate waste (sweat)– Helps produce vitamin D which is important

for the absorption of calcium.

Nose: sensory organ associated with smell. Gives the ability to perceive odours from different bodies carried by the air.

Nostrils: Opening to nasal cavity

Olfactory Nerve: Transmits impulse to cerebrum.

Olfactory epithelium: contain nerve cells sensitive to odours. Location: top of nasal cavity. Converts to nerve impulses.

Olfactory Bulb: Transmits impulse from epithelium to olfactory nerve.

Conditions necessary for smell:

• be in a gaseous state

• contain a sufficient number of odorous molecules

• occur in a sufficiently high concentration

•Be carried by the air to olfactory epithelium.

Tongue: Muscle in the mouth containing numerous sensory receptors for taste.

Gustatory Nerve: Sends nerve impulses to cerebrum to identify tastes.

Taste buds: Sensory receptors of the tongue, located inside papillae. Sensory receptors change taste into nerve impulses and transfer to nerve.

Conditions for taste: 1) be in a solution in the saliva 2) contain sufficient # of flavourful molecules 3)contact with the papillae.

10 % Taste,90% Smell Olfactory receptors help identify foods.Other receptors:Temperature (hot and cold), Discomfort (prickly feeling)Tactile (texture) of food.

Detection of Taste: Sweet (candy), sour (lemon), salty (table salt), bitter (turnip), umami/savory (aged meat). All taste buds can detect all 5 tastes.

Musculoskeletal System: Muscles and Bones

The musculoskeletal system's primary functions include supporting the body, allowing motion, and protecting vital organs.•It is made up of the bones of the skeleton, muscles, cartilage, tendons, ligaments, joints, and other connective tissue that supports and binds tissues and organs together.

Bones

• are hard, solid organs that form part of skeleton.

• 206 bones in human body.

• Three anatomical regions:– The head– Thorax (located in the trunk includes: vertebra,

sternum and ribs)– Limbs (upper and lower)

• Primarily made up of bone cells (renewable)

• Bone tissue is hardest material in body.

• Spongy Bone has numerous small cavities.

• Compact bone is dense.

• Bones are made up of both.

Two Types of Bone

Four Categories of Bone:1. Long bones

– longer than width– Middle is thin

(diaphysis), ends are rounded (epiphyses).

– Mainly compact bone

– Centre contains bone marrow and blood vessels

– Mostly in limbs

2. Short bones: – Cubic shape– Mainly spongy bone– Mainly in wrists and heels

3. Flat bones:• Thin, flat and curved• Two thin layers of compact

bone with spongy bone in between.

• Found in skull, ribs, sternum, scapula

• Makes up spinal column

Function of Bones• Support: forms rigid structure creating framework of

body giving support and anchorage for organs. Allows for posture.

• Protection of internal organs: cranium (brain), thoracic cage (heart, lungs), spinal column (spinal cord).

• Movement: levers for muscle movement. Ex: upper and lower limbs. Creates structure that is rigid and flexible. Ex: spinal column.

• Storage: cavities store fat, tissue: minerals (calcium and phosphorus).

• Production of Blood Cells: Bone marrow produces formed elements: red blood cells, white blood cells and platelets.

Joints• Junction between two or more bones.

• Provide mobility and firm connection.

• Almost all bones have at least 1 joint.

• Vary in structure– Some contain a joint capsule filled with synovial synovial

fluid fluid for lubrication. • Reinforced with ligamentsligaments: fibrous bands of tissue.• Allows for freedom of movement.

– Some extremities are protected by cartilage: whitish, elastic, smooth tissue.

Mobility of Joints• Fixed: no movement.

Ex: connecting bones of the skull to protect the brain.

• Semi-moveable: some movement allowing for flexibility. Ex: connecting all vertebrae

• Freely moveable: full mobility. Ex: elbow and hip

Mechanics of Joints

• MobilityMobility: allows for body’s various movements.

• ExtensionExtension: increases angle between bones.

• FlexionFlexion: decreases angle between bones.

• AbductionAbduction: increases distance between a limb and midline position.

• AdductionAdduction: decreases distance.

• RotationRotation: movement of a bone around an axis.

Muscles• Fibres found on bones and various organs allowing the body and internal organs to move.

• Shapes body

Functions of Muscles• Movement

– Move limbs and organs both voluntary and involuntary.

• Muscle contraction shortens length of muscle then returns to original position.

• Posture Maintenance– Continuously contracting and releasing to maintain body

posture.

• Joint Stabilization– Muscle movement supports and stabilizes joints

• Heat Release– 75% of energy expended changes to heat.– Lost energy maintains body temperature at ~37oC.

Antagonistic Muscles• Are antagonist and agonist muscles that often

occur in pairs.

• As one muscle contracts, the other relaxes.

• Ex: 1the biceps and triceps; to contract - the triceps relax while the biceps contract to lift the arms. 2Quads (contract) and hamstrings (lengthen).

Three Types of Muscles• Skeletal MuscleSkeletal Muscle

– Striated, Voluntary muscles – Attached to bones, contract for movement (bicep, quadricep)– Reaction quick, strong– Tire easily, require rest periods, little endurance– Covered with conjunctive tissue (gives power); ends are fused

forming a tendon which attaches it to bone.• Smooth MuscleSmooth Muscle

– Not striated, Involuntary muscles– Walls of some internal organs (stomach, bladder, uterus)– Help substances move from place to place– Weaker than skeletal muscles, but function longer– Higher endurance (work slowly but tirelessly)

• Cardiac MuscleCardiac Muscle– Muscle of the heart; similar to skeletal muscles.– Involuntary muscle– Great strength and endurance