Bio 2 Nervous and Muscular Systems

Central Nervous System

brain, brain stem, spinal cord

Peripheral Nervous System

all other parts of nervous system besides brain and spine

The PNS is organized into _______ .

nerves

Cnidarians and Ctenophores have what in place of the nervous systems seen in mammals for example?

nerve nets

Arthropods have a _____ spinal cord and vertebrates have a ______ spinal cord.

ventral; dorsal

Three major regions of the brain:

forebrain, midbrain, hindbrain

Which region of the brain has had the most dramatic changes in terms of evolution?

forebrain

Cerebellum is for ________

balance

Medulla Oblongata controls…

breathing, and flight or fight response

Pituitary Gland

Controls growth and development and the endocrine glands

Autonomic Nervous System

Part of PNS that controls involuntary movements and effectors other than skeletal muscle effectors

Two types of neurons:

1. Sensory

2. Motor

Sensory Neurons

Carry signals from organs to the CNS

Motor Neurons

Carry signals to muscle cells

Action Potential

state of reversed polarity; cell membrane is depolarized

Neurons are ________ cells.

excitable

Presynaptic

conducts signals into synapse

Postsynaptic

conducts signals away from synapse

Dendrites

carry signals to cell body

Cell Body

nucleus and organelles; process of integration

Axon

conducts action potential away from cell

Voltage gated channels respond to changes in what?

membrane potential

Stretch gated channels respond to what?

tension on cell membrane

Ligand gated channels respond to what?

chemicals non-covalently binding with their receptors

Resting Potential

K+ leak channels are open and Na+ and K+ channels closed; negative potential at about -70mV

Depolarization

K+ leak channels are open, Na+ channels open and K+ channel closed

Repolarization

K+ leak channel open, Na+ channels close, K+ channels open

True or False: Chemical synapses are the most common.

True

In a chemical synapse the signal is passed without direct ______ .

contact

Synaptic Cleft

in a chemical synapse this separates the pre-synaptic and post-synaptic cell

True or False: Electrical synapses do not involve neurotransmitters.

True

Electrical synapses pass signals with ______ .

contact

What are released into chemical synaptic clefts?

neurotransmitters

Process of Neuron Communication

1. Ca 2+ enters the pre-synaptic neuron

2. This causes vesicles with neurotransmitters to fuse with the pre-synaptic cell membrane

3. Neurotransmitters are released into the synaptic cleft and bind to receptors on post-synaptic membrane

4. Ligand gated ion channels illicit action potential in post-synaptic neuron

Knee Jerk Reflex

• skips the brain

• involves stretch receptors

Joints

place where 2 or more bones come together

Tendons

flexible connective tissue that connects muscle to bone

Tendons extend across ______ .

joints

Muscles can only exert force in _____ direction.

one

Muscles work in _____ pairs.

antagonistic

Actin

thin filament made of twisted chains of actin monomers

Myosin

thick filament made of many molecules with heads projecting at sides

Sliding Filament Theory

1. A motor neuron stimulates a muscle fiber.

2. Myosin filaments attach to and pull on actin filaments.

3. The actin filaments slide over the myosin filaments.

4. The sliding of the filaments pulls the Z discs of a sarcomere closer together.

5. The sarcomere shortens, and the muscle contracts.

Sarcomere

the basic unit that controls changes in muscle length.

Power Stroke

• when myosin head binds, it changes shape pulling the actin filament towards the M band

• ATP is hydrolyzed and this release of energy causes myosin to disconnect and unbend

Muscle cells are ______ cells.

excitable

Muscle fibers come into contact with axons of ______ neurons and neuromuscular junctions.

motor

Action potentials travel along _____ which run close to the sarcoplasmic reticulum.

transfer (t) tubules

Botulinum Toxin

Decreases the release of acetylcholine

Myasthenia Gravis

Disease that destroys acetylcholine receptors

3 Ways to Supply ATP:

1. immediate system

2. glycolytic system

3. oxidative system

Immediate System

uses performed ATP and creatine phosphate; produces ATP very quickly but in small amounts

Glycolytic System

synthesizes ATP by anaerobic glycolysis producing lactic acid; supplies ATP at a high rate but is self-limiting

Oxidative System

Aerobic breakdown; can operate for long periods of time, but produces ATP slowly

Slow Oxidative Cells

• red

• high levels of myoglobin

• many mitochondria

• contract and develop slowly

Fast Glycolytic Cells

• White

• high levels of enzymes for glycolytic ATP synthesis

• few mitochondria

• lack myoglobin

• fatigue rapidly

Resistance Exercise

generate large forces, causing the amount of actin and myosin to increase

Through resistance exercises ________ cells transform to ________ cells.

oxidative; glycolytic

Endurance Training

Long distance running or cycling

Through endurance training __________ cells are transformed into ____________ cells.

glycolytic; oxidative

3 Muscle Types Found in Vertebrates:

1. Skeletal

2. Cardiac

3. Smooth

2 Muscle Types Found in Invertebrates:

1. Asynchronous Flight Muscle

2. Catch Muscle

Hydrostatic Skeleton

body or body part becomes stiff and skeleton like because of high fluid pressure inside

Catch Muscle

adductor muscle pulls shells together (ex. clam)

Arthropods have an exoskeleton composed of _______ .

chitin

Exoskeleton Relation to Muscles

• muscles attached to inward projections called apodemes

• muscles pull on exoskeleton when they contract by pulling on the apodemes

Asynchronous Flight Muscles

• each excitation results in many contractions

• at high frequencies, maintain higher efficiency and greater output of power than synchronous muscles

Electric Eels and Rays

• little actin and myosin

• tiny voltage differences across cell membranes of many cells all add together when cells are excited during an electric pulse