Chapter Four Bio Exam

Identify the functions of the skin

1. protects your body against infections and extreme temperatures
2. maintains your balance of fluids
3. synthesizes vitamin D for personal use

Identify the layers of the skin

Epidermis, (stratified squamous), dermis (dense, irregular connective tissue) , hypodermis (adipose tissues)

Describe features of the epidermis

first layer of skin (outermost), layer that always flakes off, avascular (wont bled if scraped), stratified squamous, regeneration happens lower

describe features of the dermis

many collagen/elastin fibers, contain nerve fibers and blood vessels

describe features of the hypodermis

made of adipose tissue, provides insulation/energy storage, and helps anchor skin

Describe the layers of the epidermis outermost to innermost

stratum corneum, stratum lucideum (only found in thick skin), stratum granulosum, stratum spinosum, stratum basale (connects epidermis to dermis and cell regeneration happens here)

Label the following diagram

1. hair shaft
2. stratum corneum/sweat pores
3. sweat gland
4. sebaceous gland
5. blood capillaries

Also pictured: arrector pili muscle, hair follicle, adipose tissue, blood vessels, viable epidermis

a. epidermis

b. dermis

c. hypodermis

What are the functions of bone (the skeletal system)

1. support- anchors organs, holds the body upright
2. movement- bones act as levers for muscles to pull
3. protection-prevents damage to soft tissue and organs
4. storage- stores minerals like calcium and phosphorus, fat stored in the marrow
5. hematopoiesis- produces blood cells within the marrow

What is compact bone?

\-dense with few spaces

\-is primary component in long bones (arm and leg bones where greater strength is needed)

What is spongy bone?

\-”coral-like” or lattice appearance

\-lots of space

\- hold red bone marrow

\-ends of long bones, ribs, skull, pelvis, and vertebrae

What is yellow bone marrow and where is it found?

\-Found in the shaft of long bones

\-Used for fat storage

What is red bone marrow and where is it found?

\-Only found in some bones within adults- more in infants

\-found at the ends of long bones in spongy bone

\-Blood cell formation

What is the structure of an osteon?

1. Structural unit of compact bone
2. Osteocytes (bone cells) arranged in concentric circles (lamella) around the central canal
3. Lacuna = space in the hard extracellular matrix - osteocytes here
4. Tiny canals (canaliculi) within the osteon connects the osteocytes to each other and the central canal

Use packet to label the structures of long bones!!

Describe the steps of bone formation

Step 1-a cartilaginous model of the future bone forms

Step 2-Osteoblasts form a collar of bone around the shaft of the model

Step 3-The shaft of the cartilage model begins to hollow and spongy bone fills the space. Blood vessels continue to penetrate the area

Step 4-Secondary centers of bone formation develop in the ends of the bone

Step 5- cartilage remains only on the surfaces that rub and in the growth plates

Describe the step of fracture repair

1. Hematoma: Blood clot forms at spot of break
2. Fibroblasts form a cartilage/collagen callus around the break
3. Osteoblasts convert cartilage to bone (bony callus)
4. Bony callus broken down to remodel the bone back to normal size

What is the role of osteoblasts?

build and create bone

What is the role of osteoclasts?

break down bone

What is the role of fibroblasts?

production of the rich ECM of connective tissues

What makes up the axial skeleton?

\-the bones in your skull, small bones of your middle ear, hyoid bone of your neck, vertebra, and your ribcage

\-supports the upright position and protects internal organs

What makes up the appendicular skeleton?

\-the upper and lower extremities, which include the shoulder girdle and pelvis.

\-aids in the movement of the body

Name the three types of joints

Fibrous-immovable/synarthrosis (found in the skull)

Cartilaginous-semi movable/ amphiarthrosis (found in vertebrae)

Synovial-freely movable/ diarthrosis (found in hips)

Name the different synovial joints and provide an example for each

Plane-Between tarsal bones

Hinge- elbow

Pivot- between vertebrae

Condylar-between radius and carpals bones of wrist

Saddle-between carpal and metacarpal bones

Ball & Socket-Hip

Refer to packet for structure of synovial joints!

What is extension and flexion?

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What is abduction and adduction?

What is rotation?

What is dorsiflexion vs. plantar flexion?

What is inversion and eversion?

What is supination and pronation?

Name four characteristics of all muscle types?

1. Excitable-Respond to stimulus

2\. Contractile- tissue can shorten

3. Extensible- ability to stretch

4\. Elastic- can return to original size

How do synergistic muscle work? provide an example

\-They create the same movement.

\-Example: the liacus, psoas major, and rectus femoris all can act to flex the hip joint.

How do antagonistic muscle work? provide an example

\-They cause opposing movement

\-When you perform a bicep curl the biceps will be the agonist as it contracts to produce the movement, while the triceps will be the antagonist as it relaxes to allow the movement to occur.

What is the origin of a muscle?

The anchor/ point of attachment that does not move during contraction

What is the insertion of a muscle?

The “pull point”/ the point of attachment that moves during contraction

Use the packet to remember the structure of a muscle and structure of a sarcomere!!

What is the sliding filament theory?

1. Myosin head split ATP and become reoriented and energized
2. Myosin heads bind to actin forming cross bridges
3. Myosin heads rotate toward the center of the sarcomere (know as a power stroke)
4. As myosin heads bind ATP, the cross bridges detach from actin
5. Repeat

Name the steps of contraction by a motor nueron

1. Action potential arrives at a neuromuscular junction
2. Acetylcholine is released, then binds to receptors, and opens sodium ion channels, leading to action potential in the sarcolemma
3. Action potential travels down the t-tubles
4. Calcium is released from the sarcoplasmic reticulum
5. Calcium binds to troponin causing cross bridges to form between actin and myosin- causing contraction

What is the role of troponin in contraction?

Calcium interacts with tropomyosin to unblock active sites between the myosin filament and actin allowing cross-bridge cycling.

What is the role of tropomyosin in contraction?

Tropomyosin blocks myosin binding sites on actin molecules, preventing cross-bridge formation, which prevents contraction in a muscle without nervous input.

Know the action of muscles from the table in lab 8!!

What is a motor unit?

All muscle fibers stimulated by one motor neuron

* Small motor unit- small number of fibers stimulated
* Large motor unit-large number of fibers stimulated

What is recruitment?

Stimulation of multiple motor units to trigger a stronger contraction

What is a muscle twitch?

Single stimulus, weak contraction

What is a summation?

Repeated stimulus that occur prior to full relaxation, leads to a stronger contraction

What is a tetanus?

Rapid, repeated stimulus that occurs without relaxation, strong/smooth contraction

What is ATP used for in muscles?

Reactivates myosin in cross bridge cycling, pumps calcium back into sarcoplasmic reticulum, resets sarcolemma ion balance so it can be triggered again by motor neuron.

What is creatine phosphate used for in muscle contraction?

formed during time of rest, during active periods it is converted to creatine and produces useable ATP

Describe an anaerobic pathway

without oxygen, uses glucose then lactic acid, used for high intensity/ short duration activity

Describe aerobic cellular respiration

with oxygen, glucose + oxygen= carbon dioxide + water, used for prolonged activity

Define the properties of a slow twitch muscle

● Contract slowly when stimulated

● High endurance (can contract for longer amount of time before becoming fatigued)

● Darker in color due to high amount of myoglobin (which stores oxygen)

● Can produce ATP aerobically for long periods of time

Define the properties of a fast twitch muscle

● Contracts quickly and powerfully when stimulated

● Fatigues easily

● Lighter in color

● Relies more heavily on anaerobic respiration

Label the neuron diagram

What are oligodendrocytes

Oligodendrocytes are the myelinating cells of the central nervous system (CNS).

What are Schwann Cells

A type of glial cell of the peripheral nervous system that helps separate and insulate nerve cells.

What is the function of an axon

electrical impulses from the neuron travel away to be received by other neurons.

What is the function of a dendrite

Dendrites receive synaptic inputs from axons

What is the resting membrane potential of neuron?

\-70 Mv

At rest, where is there a high concentration of sodium ions (Na+), potassium (K+),
and larger, organic anions?

Outside = more Na

Inside = more K+ and negative ions

How does the sodium-potassium pump maintain resting membrane potential?

\-Pumps three sodium ions out and two potassium ions in

Uses ATP

Describe how action potential works

1. Depolization- voltage-gated sodium channels open, Na+ enters the cell, membrane potential increases (becomes more positive)
2. Repolarization- voltage gated potassium channels open, potassium ions leave the cell, membrane potential decreases/ becomes more negative

3\. Return to rest- All voltage-gate channels closed and Na-K pump restores resting membrane potential (-70 mV)

Describe the process of synaptic transmission

Step 1: Impulse reaches synaptic knob opening calcium channels and calcium enters the cell

Step 2: Vesicles release neurotransmitters into the cleft

Step 3: Neurotransmitter moves across the cleft and binds to receptors

Step 4: Ion channels open and ions move

What are excitatory neurotransmitters

opens sodium channels, allows sodium to enter, causes depolarization- creates action potential

What are inhibitory neurotransmitters

they open potassium channels, allows potassium to enter, causes hyperpolarization

What makes up the CNS and what is the function?

the brain and the spinal cord; controls how we think, move, learn and carries messages to body

What makes up the PNS

cranial and spinal nerves

What does the sensory division of the PNS do?

sensory=input, somatic (voluntary movements)

What does the motor division of the PNS do?

Motor= output, somatic and autonomic

What is the parasympatheic condition?

adjust body function to conserve energy- calm mode

What is the sympathetic condition?

prepares body for fight or flight response

What are meninges?

Protective layers of the CNS

List three types of meninges

dura, arachnoid, pia

What is the function of the frontal lobe

thinking, planning, decision making

Label the lobes of the brain

what is the function of the parietal lobe

perception and spelling

what is the function of the occipital lobe

Vision

what is the function of the temporal lobe

memory, understanding, and language

What is the function of the cerebellum

Responsible for sensory-motor coordination, balance and equilibrium, posture, etc.

What makes up the brain stem (in order from top to bottom)

midbrain, pons, medulla oblangada

What is the function of the brainstem

Controls reflexes, breathing, heart rate, blood pressure

What makes up the dienceophalons and what are their functions

thalamus (sorts and relays impulses to cerebrum), hypothalamus (regulates body temp and thirst) and the pituitary gland

What is reflex arc

Allows for rapid response
to a stimulus

What does a mechanoreceptor sense

Physical force

What does a thermoreceptor sense

tempature

What does a photoreceptor sense

light

What does a chemoreceptor sense

chemicals

What does a nociceptors sense

pain and physical damange