a&p 120 exam 2 study guide Chapter 8, chapter 9 and diffusion and osmosis

what are the functions of the muscular system Name as many of the functions of muscle tissue (all kinds) as you can

1. BODY MOVEMENTS require skeletal muscles, bones, and joints to work together
2. BODY STABILITY requires skeletal muscle contractions to help maintain body positions
3. MOVING SUBSTANCES within the body
-a) Every time your heart beats it moves blood
-b) Every time your mouth makes saliva
-c) Every time your stomach and intestines churn your food
4. Heat production is a by-product of friction caused by muscle tissue contracting, especially skeletal muscle(and mitochondrial work)

what is special about muscle tissue

can shorten or contract to produce movement and is well supplied with blood vessels 

what is a muscle

organs divided by fascicles

what are fascicles

bundle of muscle fiber (cells)

what are muscle fibers

muscle cells containing myofibrils

what is sarcoplasmic reticulum and what does it do

specialized form go the endoplasmic reticulum of muscle cells

stores calcium and releases it into sarcoplasm when the t tubule converts an action potential 

what is neuromuscular junction and what does it do

synapse between a motor neuron and a skeletal muscle fibers 

ensures precise control of skeletal muscle contraction and voluntary movement

what is a neurotransmitter and what is acetylcholine 

chemical messanger used by a neuron to transmit an impulse across a synapse to another cell 

acetylcholine is the neurotransmitter released 

how does a muscle fiber contract

1. Signal arrives at the neuromuscular junction. A motor neuron fires and releases acetylcholine (ACh) into the neuromuscular junction.

2. Sarcolemma is excited. ACh binds receptors on the sarcolemma (muscle cell membrane), creating an electrical impulse that spreads across the fiber and down T-tubules.

3. Sarcoplasmic reticulum releases calcium. The impulse triggers the sarcoplasmic reticulum to release calcium (Ca²⁺)into the cytoplasm.

4. Calcium binds troponin. Ca²⁺ binds to troponin on the thin myofilament (actin), causing tropomyosin to move and expose actin’s myosin-binding sites.

5. Cross-bridge formation. Myosin heads (thick myofilaments) bind to the exposed sites on actin, forming cross-bridges.

6. Power stroke — contraction of the sarcomere. Myosin pivots, pulling actin toward the center of the sarcomere and shortening the distance between Z lines — this shortens the sarcomere and produces contraction.

7. ATP allows release and reset. ATP binds to myosin, causing myosin to detach from actin; ATP is then hydrolyzed to “re-cock” the myosin head for another cycle.

8. Relaxation. When neural stimulation stops, ACh is removed, Ca²⁺ is pumped back into the sarcoplasmic reticulum, troponin/tropomyosin cover the binding sites again, cross-bridges cease, and the sarcomere (and muscle) returns to resting length.

what is the thick filament of the sarcomere and what is the thin filament

sarcomere is the filaments arranged in functional units

thick is myosin 

thin is actin 

what are skeletal muscles and where are they found

voluntary muscle and acts on levers to pull

found in arms, legs, etc 

what is smooth muscle cells and where are they found

act involuntarily, usually attached  to the soft tissues 

what is cardiac muscles cells and where are they found 

unique physiology, only found in the heart and is involuntary 

active transport

movement of molecules across a membrane using energy

diffusion 

movement of molecules from an high concentration to a low concentration

filtration

movement of water and small particles through a membrane

osmosis

movement of water across a aslecteivly permeable membrane from low to high concentration

hypertonic

more solute

less like water

hypotonic

less solute

more like water

isotonic 

equal parts solute and like water

what is the difference between diffusion into and out of a cell and osmosis into and out of a cell

what does it mean if a membrane is permeable to a solute? what does it mean of the membrane is not permeable to a substance how does this relate to diffusion and osmosis?

if membrane is permeable to a solute —> solute can pass through freely

not permeable to a solute. —> solute cannot cross

diffusion - solute and membrane can move

osmosis - only water can move

explain what happens to a cell (RBC) placed in a hypertonic solution a hypotonic solution and an isotonic solution

hypertonic solution. - the cells chunks and shrivels (water moves out)

hypotonic solution - the cell swells and may burst if too much water enters (water moves in)

isotonic solution - water solute concentration (water moves in a and out equally)

what is sensory perception

sense our external and internal environment

what is integration

allows us to perceive what those sensation mean - allows us to decide what action to take

what is motor function

allows us to move in response to a decision

what is special about neurons 

neurons responds to stimuli like muscle cells

what are the four CNS glial cells

oligodendrocytes

astrocytes 

microglial 

ependymal 

which glial cells make the myelin sheath

oligodendrocytes

which feed and nourish the CNS neurons

astrocytes

which defends the CNS from attack

microglial

which makes CSF 

ependymal

which glial cell makes CSF and what does CSF stand for

ependymal; cerebrospinal fluid

what is the most important glial cell of the peripheral nervous system and what does it do

Schwann cells, responsible for myelin production

cell body function

holds nucleus

axon function

takes info away from the cell body

dendrites function 

takes info toward cell body

nissl body function

modified rough ER of neurons; synthesize proteins

synapse function

axon of one neuron meets the dendrite or cell body of another neuron

axon hillock function

the axon arises from the cell body as a cone shaped thickening

voltage gate channels location, resting graded or action

axon; action potential

ligand-gated channels location, resting graded or action

dendrites or cell body; graded potential 

na/K pumps location, resting graded or action

entire neuron; resting membrane potential

k leakage channels location, resting graded or action

entire neuron; resting membrane potential

What is the resting potential? Is the membrane positive on the inside or negative? Describe how the resting potential is established using the terms sodium-potassium ATPase and leakage channels.

the difference in electric charge between the inside and outside of a neurons cell membrane

Describe the action potential of a neuron using the terms synapse, neurotransmitters, resting membrane potential, dendrites, axons, all-or-nothing, voltage-gated channels.

outside positive; inside negative (think a clown)

what part of the neuron will i find an action potential 

axon 

what part will i find granted potentials

dendrites or cell body

what part of the neuron releases neurotransmitters

axon and diffuse across the synapse

what part of the neuron receives neurotransmitters

dendrites

what is the difference between graded and action potentials

a graded potentials can result from a opening of chemically gated channels (dendrites)

action potentials require the opening of voltage gated channels (axons)

which protein causes graded potential and where is it found 

neurotransmitters, ligand gated proteins

depolarization in graded potentials

less negative value —> making it more likely to fire an action potential

hyper polarization in graded potentials

makes the inside of the cell more negative —> less likely to fire action potential 

threshold potential in graded potentials

specific voltage a neurons membrane must reach to trigger an action potential

Explain saltatory conduction using the terms action potential, distribution of Na/K pumps, Schwann cell, oligodendrocyte, myelin, myelin sheath and nodes of Ranvier. What makes saltatory conduction such a great
innovation for action potentials? Does it happen in the brain or the peripheral nervous system or both?

electrical impulse skips from node to node down the length of an axon

What does myelin do for the nervous system and is myelin neurotransmitter

insulating layer or sheath that forms around nerves 

allows electrical impulses to transmit quickly and efficiently along the nerve cells 

function and location brain stem

autonomic

function and location cerebellum

refinement of motion

function and location cerebrum

thinking 

function and location diencephalon

unconscious