exam 1

Question 1

1. Define the characteristics and features of epithelial tissues.

Answer 1

Epithelial tissue: covers surfaces, lines internal passages and chambers, produces glandular secretions
Epithelial tissue gets its nutrients from underlying blood vessels through diffusion
It lines every body surface/structure,
Function of epithelial tissue:
1.protection -from abrasion, chemicals, secrete protective substances
2. control permeability
3. secretion-produce and secrete substances
4. simple diffusion
5. absorption-transcellular transport
6. surface parallel transport

Question 2

simple squamous

Answer 2

Most delicate epithelium in body, found in protected regions where diffusion or other forms of transport take place Line chambers and passageways that do not communicate with the outside world Endothelial lining of heart and blood vessels, inner lining of cornea, alveoli of lungs

Question 3

Simple Cuboidal

Answer 3

Look like little hexagonal boxes and appear square in typical sectional views
Each nucleus is centrally located Provide limited protection Found in regions where secretion and absorption takes place
Ex: kidney tubules are lined with them

Question 4

Stratified cuboidal

Answer 4

Look like circular layers of cuboidal cells Line some ducts, are rare
Found in ducts of sweat glands and mammary glans

Question 5

Non-Ciliated Simple Columnar (with microvilli)

Answer 5

Height is greater than width
Nuclei typically in basal portion (lower part) of cell Provide protection- slightly more protection than simple cuboidal epithelia, are used for secrection and absorption as they have microvili Lining of stomach, intestines, gallbladder

Found where absorption or secretion occurs

Question 6

Stratified columnar epithelia

Answer 6

Rare

Has 2 or more layers Pharynx, urethra, anus, a few large excretory ducts

Question 7

Stratified Squamous

Answer 7

Cells form a series of layers, occur where mechanical stresses are severe
can be keratinized or nonkeratinized
-on surfaces where mechanical stress and dehydration are potential problems, the apical layers of epithelial cells are packed with keratin= tough and water resistant
-nonkeratinized also resist abrasion but must be kept moist or will dry out, so occur in oral cavity, oesophagus Surface of skin, lining or oral cavity, throat, anus, vagina

Question 8

Ciliated Pseudostratified Columnar

Answer 8

A specialized columnar epithelium that includes a mixture of cell types
Because the cells nuclei are located at varying distances from the surface, the epithelium looks stratified.
However, all the cells rest on the basement membrane so it is actually a simple epithelium
The surface epithelial cells possess cilia Protection and secretion Line most of the nasal cavity, trachea, bronchi and also portions of the male reproductive tract

Question 9

Transitional epithelium

Answer 9

In empty urinary bladder the transitional epitheloum seems to have many layers and its outermost cells are rounded or balloon-shaped cuboidal cells,
As the bladder fills and stretch, transitional epitheloum resembles a stratified, nonkeratinized epithelium with 2 or 3 layers Can stretch without damaging the epithelial cells Line the renal pelvis, ureters and urinary bladder

Question 10

3. Explain how the characteristics of epithelial tissue can contribute to pathology.

Answer 10

1) intercellular junction
a. tight junctions= gatekeppers
b. adhering junctions= support and stability. Hold cells together like a belt so they don’t separate
c. desmosomes= support and stability
d. gap junctions= easy cell to cell communication

2) Epithelial maintenance and renewal- regeneration is key
Carcinoma- malignant tumor of epithelia
Adenocarcinoma- malignant tumor from glandual epithelial cells.

3) Apical surface features
a. microvilli- maximize surface area for absorption and transcellular transport
b. cilia- highly motile, no absorption, but allow for surface parallel transport

Question 11

5. Describe the characteristics of connective tissue and compare different types of connective tissue in the body.

Answer 11

Connective tissue are the most common, diverse and widely distributed of the 4 tissue types.
They are composed of some cells and abundant extracellular matrix. Their cells differ with the different connective tissue types.
Connective tissue is made of:
-ground substance- found between fibers and cells of CT
-protein fibers- provide support, there are 3 types:
1. elastic fibers: have recoil, can stretch and return to original shape
2. reticular fibers: provide shape and structure. Form a branching interwoven structure that allows them to resist forces applied from many different directions and stabilize organs, bloodvessels and nerves.
3. collagen fibers: strongest and most common fibers, can resist tension= have tensile strength. Tendons and ligaments mostly made up of these

connective tissue:
1. supporting connective tissue
>bone
>cartilage
2. fluid connective tissue
>blood 
>lymph
3. connective tissue proper
>dense: dense regular, dense irregular
>loose: areolar, adipose, reticular

Question 12

Metaplasia

Answer 12

normal epithelia from one area replaced by another form of epithelia not typical for that region.
Changes in epithelia0 result of smoking or other sort of harmful chemical, so the body changes the tissue for protection. This can be bad because, ex: the body changes the cells and the cilia are replaced= why chronic smokers would cough more since they can’t move mucus
Changes in cells also greatly increases your risk of cancer.

Question 13

connective tissue proper

Answer 13

Connective tissue proper:

1. Loose connective tissue: packaging material of the body, fills spaces between organs, provides cushioning and supports epithelia, blood vessels and nerves
   a) areolar tissue: widely distributes, highly vascular so drugs injected into it get absorbed quickly, contains all 3 fibers. Function is to act as packaging tissue and fill spaces
   b) adipose tissue: adipocytes (fat cells), highly vascular, functions as fat/nutrient storage, insulation, padding/protection
   c) reticular CT: network of reticular fibers in loose ground substance, has lots of reticular fibers, used in organs where we need structure but also gives organs shape
2. Dense connective tissue:
   a) dense regular CT: has parallel thick collagen fibers- aligned parallel to applied forces. sAre strong ex: tendons
   b) dense irregular connective tissue: mainly thick collagen fibers in a random arrangement. Can resist forces in multiple directions. Except at joints, dense irregular connective tissue forms a sheath around cartilage.

Question 14

1. Describe characteristics and functions of all muscle tissue.

Answer 14

The major characteristics of muscle tissue is that they can all contract, they are all excitable (ability to respond to stimulation), they are all extensible (can contract), and they are all elastic (can recoil).

The functions of muscle tissue include the following:
Muscle tissue produces movement, as seen in bones (skeletal muscle tissue) and urine (smooth muscle tissue).
They open and close passageways. This is seen in sphincters, which are made up of smooth muscle tissue and open and close different organs.
Muscle tissue maintains posture and stabilizes joints. This is seen in skeletal muscle. Finally, muscle tissue generates heat. When a muscle contracts, it releases energy, and therefore releases heat.

Question 15

2. Describe the characteristics, properties, and functions of skeletal muscle tissue.

Answer 15

The functions of skeletal muscle tissue are:

• To produce skeletal movement.
• To maintain body posture.
• To support soft tissue.
• To regulate the entry and exit of material, as they encircle the openings of the digestive and urinary tracts.
• To maintain body temperature. Muscle contractions produce energy, which in turn produces heat.

There are three layers of the skeletal muscle tissue. The outer layer is the epimysium. The middle layer is the perimysium (which wraps the fascicle). The inner layer is the endomysium (between individual muscle fibers).
Tendons are where all three of these layers come together and attach the muscle to the bone.

Question 16

3. Compare and contrast skeletal, cardiac, and smooth muscle.

Answer 16

Skeletal muscle tissue:
is found combined with connective muscle tissue and neural tissue in skeletal muscles.
Functions of skeletal muscle tissue include:
To move/stabilize the skeleton.
To guard the entrances and exits to the digestive, respiratory, and urinary tracts.
It generates heat.
It protects internal organs.
It has 3 types of fibers:
a) Slow oxidative fibers- aerobic, endurance, uses O2 for fuel
b) Fast oxidative- intermediate
c) Fast glycolytic fibers- fastest contraction, can’t hold contraction for very long but more powerful. Anaerobic, instantaneous power.

Cardiac muscle tissue:
is found at the heart.
It functions to circulate blood and maintain blood pressure.

Smooth muscle tissue:
is found on the walls of blood vessels and the digestive, respiratory, reproductive, and urinary organs.
Its functions include: To move food, urine, and reproductive secretions.
It also controls the diameter of respiratory passageways and controls the diameter of blood vessels.

Question 17

4. Describe the gross anatomy of skeletal muscle tissue.

Answer 17

Skeletal muscle is made up of fascicles. Fascicles are made up of skeletal muscle fibers (aka cells). They run the entire length of the muscle. Muscle fibers are made up myofibrils.
Myofibrils are cylindrical structures extending the entire length of the muscle fiber, contain myofilaments.
Myofilaments consist of the proteins actin and myosin, which cause the striations of skeletal muscle.
The epimysium covers the entire muscle. The perimysium fills the space between the fascicles. The endomysium fills the space between the muscle fibers. The epimysium, perimysium, and endomysium consist of connective tissue.

Skeletal muscle->fascicles->muscle fiber->myofibrils->myofilaments
Neuromuscular junction: where the motor neuron meets the muscle fiber
Motor unit: single motor neuron and all the muscle fibers it controls. Number of motor unit and degree of control provided are directly related.

Question 18

5. Explain tendons.

Answer 18

Tendons are the site where the dense regular connective tissue of the epimysium, perimysium, and endomysium unite together at each end of the muscle and attach it to the bone. Tendons are avascular and are also very strong. Some of the muscle fibers insert themselves into the bone to attach the tendon to the bone. These skeletal muscle fibers are termed Sharpey’s fibers (collagen fibers that penetrate deep into cortical bone, allows tendons to attach strongly to bone). The origin tendon (where the muscle starts) is usually on the side that doesn’t move, or the proximal side. The insertion is at the distal attachment and is usually the tendon that moves.

Question 19

6. Analyze how the size of a motor unit contributes to the function of a muscle.

Answer 19

A neuromuscular junction is where a motor neuron meets a muscle fiber. A motor unit consists of a single motor neuron and all the muscle fibers that it controls. The number of motor fibers attached to the motor neuron directly relates to how fine or gross the muscle movement is. For fine movement, you want only a few muscle fibers to be attached to the motor neuron. If you want gross movement, you want many muscle fibers to be attached to the motor neuron. It’s important to note that once a motor neuron is excited, all the muscle fibers it’s attach to contract.

Question 20

7. Describe the different types of skeletal muscle fibers.

Answer 20

The first type of skeletal muscle fiber is slow oxidative. Slow oxidative fibers require oxygen, and therefore needs blood, as myoglobins in blood carry oxygen. Slow oxidative are therefore aerobic and provide endurance. A good long distance runner would likely have more slow oxidative fibers, as it requires lots of endurance.

Fast glycolytic fibers don’t need oxygen, as they use glucose instead. Because of this, they don’t need blood, and they therefore have a white appearance. They are anaerobic and provide instantaneous power. A weight lifter, a sprinter, etc would likely have an abundance of fast glycolytic cells.

Fast oxidative fibers are in between slow oxidative and fast glycolytic.

Question 21

8. Summarize the effects of exercise and aging on muscle tissue.

Answer 21

Muscle atrophy is the loss in size of muscle, and often occurs with aging or reduced use of the muscles. When you don’t use a muscle, the myofilaments reduce in number, while the number of muscle fibers stays the same. This causes the size to decrease.
Can be caused by lack of stimulation, aging, injury

Hypertrophy is when muscles increase in size. This is due to repetitive stimulation of the muscles, such as in exercise. This causes both the myofibrils and myofilaments to increase in number, causing the muscle all together to increase in size. (we don’t get more cells, we just get bigger cells). The range of motion of a muscle is directly related to the size of a muscle. Muscles that are big and long have a large range of motion, whereas muscles that are small and short have a smaller range of motion. The more cross-sectional area of a muscle, the more force it has and the more powerful it is.

Question 22

9. Describe the four different categories of skeletal muscles.

Answer 22

a. Parallel muscles have fascicles that run parallel to the axis of the muscle.
i. Parallel muscle- biceps
ii. Parallel muscle with tendinous bands- abdominals
iii. Wrapping muscle-supinator, wrap around
b. Convergent muscle start with a broad range of fascicles and all converge at the tendon. (like a fan)
c. Pennate muscles have fascicles that feather out- like a feather, fibers enter at an angle, are strong but limited in their range of motion.
i. Unipennate- feather like
ii. Bipennate-two feathers attached together
iii. Mulipennate
Bipennate and multipennate can have more function than unipennate since there’s more angle.
d. Circular muscles have fascicles in the shape of a circle. Ex: sphincter

Question 23

1. Describe the divisions of the nervous system and their contents.

Answer 23

The central nervous system consists of the brain and spinal cord.
The peripheral nervous system consists of all nervous tissue outside of the central nervous system.
The central nervous system consists of ascending (sensory) tracts that bring information from the peripheral receptors to the processing centers of the brain. It also has descending (motor) tracts that begin at central nervous system centers and end at the effectors they control.
The peripheral nervous system consists of afferent and efferent divisions.
i. The afferent division consists of somatic and visceral sensory nerves, and it sends signals from periphery to the spinal cord.
ii. The efferent division consists of the somatic and autonomic nervous system, and sends info away from the spinal cord to the receptors.
a. Autonomic is divided into parasympathetic and sympathetic division
The autonomic nervous system functions of the body that are not under conscious control, such as heart rate, digestive processes, etc. It consists of the parasympathetic and sympathetic divisions.
A. The sympathetic nervous system controls the “fight or flight” response,
B. while the parasympathetic nervous system causes the body to relax after such a response.

Note - an ascending pathway goes from the periphery to the brain. A descending pathway goes from the spinal cord to the receptors.

Question 24

2. Identify the different types of neurons and glial cells and their functions.

Answer 24

3 types of nerons
1. bipolar neurons
2. pseudounipolar neurons
multipolar neurons
Glial cells do not send signals, but they create the environment needed for signals to be sent. They provide protection, insulation, and nourishment for neurons. They provide an overall supportive scaffolding for neurons. Unlike neurons, they can divide and therefore regenerate throughout life. They are 5x more abundant than neurons, but because they are smaller, they only consist of half the mass of the brai
glial cells of CNS are astrocytes, microglia, ependymal cells, oligodendrocytes
glial cells of PNS are satellite cells and schwann cells

Question 25

neuron characteristics

Answer 25

All neurons carry electrical signals, live for a lifetime, cannot divide, and have a high metabolic rate (need a constant blood supply for energy). Most cell bodies are located in the central nervous system, or are at least close to it, because the bones surrounding the CNS allow the cell bodies to be better protected.

A synapse is where neural communication occurs. There are presynaptic and postsynaptic neurons. A synapse can either be with another neuron, with a muscle, or with a gland. The synapse with the muscle and gland are effector cells.

Question 26

1. Bipolar neurons

Answer 26

1. Bipolar neurons are the most rare type. The cell body is in the middle. They are involved in sight, smell, and hearing. Fine dendrites fuse to become a single dendrite, then goes to cell body, then goes to axon.

Question 27

2. Pseudounipolar neurons

Answer 27

2. Pseudounipolar neurons are also rare, just not as rare as bipolar neurons. They start off with multiple dendrites, have a long axon, the cell body is in the middle and hangs off, and ends with the axon terminals. They are located in the dorsal root ganglion. Sensory neurons of the peripheral nervous system are pseudounipolar, and their axons may be unmyelinated.

Question 28

multipolar neurons

Answer 28

1. The most common type of neurons are multipolar neurons. They start as several dendrites, go to the cell body, and then go to the axon. Ex: a motor neuron that connects the CNS to skeletal muscles

Question 29

Convergence

Answer 29

Convergence occurs when several neurons fuse to become one neuron/send signals to one neuron. Can amplify a signal, also allows multiple pieces of info to come to one neuron that can make a decision based on the information.

Question 30

Divergence

Answer 30

Divergence occurs when one neuron sends a signal to multiple other neurons. This is a much more widespread signal, but is beneficial because it allows one source to send a signal to multiple other places.

Question 31

1. Astrocytes

Answer 31

Glial cell
(CNS) look like stars and are flat.  They maintain the blood brain barrier, provide structural support, hold glial cells together, regulate ion, nutrient, and dissolved-gas concentrations, absorb and recycle neurotransmitters, and form scar tissue after injury. 9

Question 32

Oligodendrocytes

Answer 32

Glial cellCNS) myelinate the axons of the CNS. The white matter of the CNS is the myelin sheath around the axons. They also provide a structural framework.

Question 33

3. Microglia

Answer 33

Glial cell
CNS) are referred to as the brain’s security force/immune system. They phagocytize waste and debris, viruses, microorganisms, and tumor cells. When an injury occurs in the CNS, the amount of microglia increases abundantly

Question 34

4. Ependymal cells

Answer 34

Glial cell
(CNS) line ventricles (brain) and central canal (the spinal cord). They monitor the composition of the cerebrospinal fluid, which is fluid in chambers outside the brain and spinal cord that consists of dissolved gases, nutrients, wastes, and other materials.  Ependymal cells controls what parts of this fluid will be passed over.  They also provide protection to brain and spinal cord.

Question 35

5. Satellite cells

Answer 35

Glial cell
(PNS) are similar to astrocytes. They surround the neuron cell bodies and regulate O2, CO2, nutrient, and neurotransmitter levels around neurons in the ganglia.

Question 36

6. Schwann cells

Answer 36

Glial cell
PNS) are similar to oligodendrocytes. They surround all axons of the PNS and myelinate them. They also participate in the repair process after injury.

Question 37

3. Explain myelination.

Answer 37

Myelination is the process of wrapping the axons of neurons in a myelin sheath. Schwann cells myelinate the axon in the peripheral nervous system. Oligodendrocytes myelinate the axons in the central nervous system. Myelination makes signals travel faster down the axon. The more layers of myelination there are, the faster the signal goes. While some neurons have many layers of myelination, some aren’t myelinated at all. However, in the PNS, Schwann cells also protect neurons in addition to myelinating them. Therefore, unmyelinated cells of the PNS are still engulfed and surrounded by Schwann cells. While Schwann cells can only myelinate a one segment of one neuron, oligodendrocytes can myelinate multiple segments of multiple neurons. They wrap around the axons of many, holding them in a clump.
1. 1.A Schwann cell first encloses a segment of the axon within a groove of its cytoplasm
2. 2.The schwann cell then rotates around the axon
3. 3.As it rotates, the inner membraneous layers are compressed and the cytoplasm is forced into more superficial layers, when complete, the myelin sheath consists only of phospholipid nilayers of the plasma membrane with the schwann cell nucleus and cytoplsm at the surface
Because each schwann cell myelinates only 1 mm of an axon, it takes many cells to myelinate an entire axon. The portion of a myelinated nerve axon between two successive schwann cells is called an internode. The small gaps that separate internodes are called nodes of Ranvier

Question 38

4. Understand the process of axon regeneration and apply that knowledge to nervous system injury and pathology.

Answer 38

This first scenario occurs in the peripheral nervous system. A fragmentation may occur that breaks the axon and the myelin sheath around it. Imagine a proximal stump on the right and a distal stump on the left. Schwann cells form a cord and grow into the cut and unite the stumps. they release a chemical that stimulates regeneration of the axons, creating a regeneration tube. Macrophages come in and clean up degenerated axon and myelin. The axon sends buds into the Schwann cells and starts growing along the cord of Schwann cells. The axon then continues to grow into a distal stump and is enfolded by Schwann cells. This regeneration is limited in the central nervous system. This is due to the fact that there are oligodendrocytes instead of Schwann cells in the CNS, and oligodendrocytes prohibit growth. In addition, astrocytes, one of whose jobs is to fill space, walls off the damaged neuron, prohibiting it from healing and growing.

Question 39

5. Describe functional classification.

Answer 39

A sensory input comes in through the CNS and goes to the brain. At the brain, integration occurs and the information is processed. The CNS then sends a motor output away from the spinal cord and towards the muscles.
Sensory afferent info ( goes towards the brain) consists of visceral sensory and somatic sensory information.
The visceral sensory system monitors things in the body that are unconscious, such as organ function and heartbeat. So it is taking info from organs= knowing we are hungry, warm etc
Somatic sensory involves more conscious things, such as sense of touch (pain, temperature). Somatic=conscious
The motor efferent consists of visceral motor and somatic motor:
The visceral motor system consists of smooth muscles, and the visceral motor is connected to the visceral sensory= sensory is constantly monitoring the motor
somatic motor consists of voluntary muscle contractions that go towards the spinal cord. Sense of touch.

Question 40

The visceral sensory system

Answer 40

Sensory afferent info ( goes towards the brain) consists of visceral sensory and somatic sensory information.
The visceral sensory system monitors things in the body that are unconscious, such as organ function and heartbeat. So it is taking info from organs= knowing we are hungry, warm etc

Question 41

Somatic sensory

Answer 41

Sensory afferent info ( goes towards the brain) consists of visceral sensory and somatic sensory information.
Somatic sensory involves more conscious things, such as sense of touch (pain, temperature). Somatic=conscious

Question 42

motor efferent

Answer 42

The motor efferent consists of visceral motor and somatic motor:
The visceral motor system consists of smooth muscles, and the visceral motor is connected to the visceral sensory= sensory is constantly monitoring the motor
somatic motor consists of voluntary muscle contractions that go towards the spinal cord. Sense of touch.

Question 43

6. Explain the role of glial cells in disease.
   Astrocytomas
   Oligodendrogliomas
   astrocytomas

Answer 43

Glial cells have shown to play a role in many diseases. There is evidence that a decreased number of glial cells in the frontal cortex has a role in depression and schizophrenia. There are also correlations between glial cells and gliomas (or tumors).

• Astrocytomas are tumors that are not well controlled and can spread far out into the brain.
• Oligodendrogliomas are more limited, and tend to stay in a close space. Oligodendrogliomas are much easier to remove because their walls are so defined,
• astrocytomas are more difficult to remove because their walls are not defined- because astrocytes are everywhere and they are wrapped arounf everything- have a very wide reach, so it is hard to know if you’re reaching everything. Oligodendrocytes are not as far reaching and have cleaner borders.

Question 44

7. Explain the structure of a nerve.

Answer 44

Nerves are only found in the peripheral nervous system and therefore are not present in the central nervous system. Nerves carry information to and from the CNS. They are surrounded by tissue.
The three layers of a nerve are the epineurium, the perineurium, and the endoneurium. The epineurium is the connective tissue that surrounds the entire nerve.
The perineurium is connective tissue that surrounds individual fascicles. A fascicle is a small group of axons. A nerve consists of many fascicles.
The endoneurium is the connective tissue that surrounds each axon within a fascicle.

Question 45

1. Describe the anatomy of the spinal cord and identify its regional variations.

Answer 45

• Adult spinal cord extends from the foramen magnum of the skull to the inferior border of the first lumbar vertebra (L1)
• The spinal cord consists of the cervical region (C1-C8- 8 nerves and 7 vertebrae) at the top, the thoracic region (T1-T12), the lumbar region (L1-L5), the sacral region (S1-S5), and the coccyx (Co1).
• Has grey matter- made of cell bodies of neuroglia, neurons, unmyelinated neuronal processes. The amount of grey matter increases in the segments of the spinal cord that deal with sensory and motor innervation of the limbs.
• Adult spinal cord grows until age 4, adult spinal cord only elongates to the forst or second lumbar vertebra, final length is about 16-18 inches, is shorter than the vertebral column
• Cauda equina- the filum terminal and the long ventral and dorsal roots are called cauda equina because looks like a horse tail
• Posterior (dorsal) horns of grey matter- contain somatic and visceral sensory nuclei
• Anterioir (ventral) horns- contain somatic motor neurons
• Lateral horns (intermediate) found only between segments T1 and L1 and contain visceral motor neurons
Gray matter makes up the horns and consists of motor cell bodies.
The dorsal root consists of only sensory neuron axons, while the ventral root consists of only motor neuron axons.
The dorsal and ventral ramus contain a mixture of motor and sensory information.
Overall, the dorsal part of the spinal cord combines sensory and motor information to innervate deep muscles and skin of the back.
The ventral part joins motor and sensory information to innervate the anterior and lateral trunks.
The lateral horns consist of visceral (autonomic) motor nuclei, which stimulate smooth muscle, cardiac muscle, and glands.
The anterior horns consist of somatic motor neurons, that stimulate skeletal muscles.

Question 46

o Cervical enlargement

Answer 46

• There are 2 special regions: cervical enlargement and lumbosacrel enlargement
o Cervical enlargement: the expanded regions of the spinal cord which supplies nerves to the pectoral girdle and the upper limbs

Question 47

o Lumbosacrel enlargement

Answer 47

: supplies nerves to the pelvis and lower limbs

Question 48

conus meduallris

Answer 48

• Below the lumbosacrel enlargement, the spinal cord tapers and forms a cone-shaped tip called the conus meduallris- located inferior to the first lumbar vertebra (L1)

Question 49

• Filum terminale

Answer 49

“terminal thread”- extending within the vertebral canal from the inferior tip of the conus medullaris. It extends from L1 to the dorsum of the coccyx where it connects the spinal cord to the first coccygeal vertebra

Question 50

dorsal root ganglia

Answer 50

• Every spinal segments has dorsal root ganglia that contains cell bodies of sensory neurons. And have dorsal roots and ventral roots
o Dorsal roots: contain afferent axons (towards brain, sensory)
o Ventral roots: anterior to dorsal root, contain efferent axons of somatic motor neurons
o The dorsal and ventral roots of each segment enter and leave the vertebral canal between adjacent vertebrae at the intervertebral foramina

Question 51

• Cauda equina

Answer 51

the filum terminal and the long ventral and dorsal roots are called cauda equina because looks like a horse tail

Question 52

• Posterior (dorsal) horns

Answer 52

• Posterior (dorsal) horns of grey matter- contain somatic and visceral sensory nuclei

Question 53

• Anterioir (ventral) horns

Answer 53

• Anterioir (ventral) horns- contain somatic motor neurons
o The size of the anterior horns varies depending on the number of skeletal muscles innervated by that segment, so the anterior horns are largest in cervical and lumbar regions of the spinal cord, regions that control the muscles of upper and lower limbs

Question 54

• Lateral horns

Answer 54

• Lateral horns (intermediate) found only between segments T1 and L1 and contain visceral motor neurons

Question 55

• White matter org

Answer 55

divided into columns
o Posterior white columns- located between the posteriior horns and posterior median succulus
o Anterior whie columns- located between anterioir horns and anteriori median fissue
o Lateral white columns- between anterior and posterioir columns
o Each column has tracts of axons carrying either sensory or motor commands
o All axons in a tract relay info in the same direction
o Small commissural tracts carry sensory or motor signals between segments of the spinal cord
o Larger tracts connect spine with brain

Question 56

• Spinal meninges:

Answer 56

3
o Pia meter- inner most, directly on spinal cord
o Arachnoid mater- there is a fluid between pia mater and arachnoid mater
o Dura mater

Question 57

• Arterial supply in spinal cord

Answer 57

o Anterioir spinal artery- single artery, supplies anterioir 2/3 of the cord, located in the antero-median fissure
o Posterior spinal artery- two arteries, supplies 1/3 of cord, located in the postero-lateral fissue

Question 58

2. Explain the functional pathways in the spinal cord.

Answer 58

Spinal cord pathways are multi-neuron pathways that carry information between the brain and the peripheral nervous system.
Ascending pathways bring sensory information to the brain, while descending pathways carry motor information to the spinal cord.
Most (90+%) of pathways decussate - cross over. This means that the left side of the brain controls the right side of the body, and the right side of the brain controls the left side of the body. Every single pathway is composed of paired tracts, meaning that they happen on both sides simultaneously and are mirrored images of each other.

Question 59

spinocerebellar pathways

Answer 59

1. Corticol spinal tract (motor pathway)- going from cortex of brain to spinal cord, controlling the voluntary, fine motor movements of the upper and lower limbs
   a. Crosses in brainstem (left to right or right to left) and synapses in the anterior horn
2. Dorsal column medial lemniscus pathway (DCML)- carries into about fine touch/discriminative touch, pressure, vibration coming from finger tips to up
   a. Crosses at brainstem
3. Anterolateral system (ALS)- carry sensation of pain, touch, crude touch (sitting in a chair versus holding a pen)
   a. Synapses at dorsal horn and crosses over before brainstem
   b. 3 neuron tract
4. Spinocerebellar tract
   a. 2 neuron tract that fo not synapse at the thalams so th eperson is not aware of the sensory info carried in the spinocerebellar tract
   b. Provides into about position of muscles, tendons, joints of lower limbs- essential for coordination of body movements

Question 60

1. Corticol spinal tract

Answer 60

(motor pathway)- going from cortex of brain to spinal cord, controlling the voluntary, fine motor movements of the upper and lower limbs
a. Crosses in brainstem (left to right or right to left) and synapses in the anterior horn

Question 61

Dorsal column medial lemniscus pathway (DCML)-

Answer 61

carries into about fine touch/discriminative touch, pressure, vibration coming from finger tips to up
a. Crosses at brainstem

Question 62

3. Anterolateral system (ALS

Answer 62

carry sensation of pain, touch, crude touch (sitting in a chair versus holding a pen)

a. Synapses at dorsal horn and crosses over before brainstem
b. 3 neuron tract

Question 63

4. Spinocerebellar tract

Answer 63

a. 2 neuron tract that does not synapse at the thalams so the person is not aware of the sensory info carried in the spinocerebellar tract
b. Provides into about position of muscles, tendons, joints of lower limbs- essential for coordination of body movements

Question 64

Upper and lower motor neurons

Answer 64

• Upper motor neurons: cell body in either the cerebral cortex or a brainstem nucleus
o Upper motor neuron excites or inhibits the activity of lower motor neurons
• Lower motor neuron: cell body in either the anterior horn of the spinal cords or a brainstem cranial nerve nucleus
o the lower motor neuron is always excitatory- axon connects directly to skeletal muscle fibers

Question 65

• Subcorticospinal pathways

Answer 65

unconscious control
o brainstem or cerebellum to spinal cord
o help regulate and control the pattern of somatic motor activity through indirect pathways
o can excite or inhibit LMNs
o may modulate spinal reflexes, regulate muscle tone and posture, control orienting reflexes to visual or auditory stimuli

Question 66

3. Predict the deficits associated with injury to specific regions of the spinal cord.

Answer 66

When a lumbar puncture is performed, the needle is inserted between L4 and L5 because the spinal cord ends at L and the cauda equina is the collection of spinal nerves that continue down, so if a needle is inserted above the L4, the spinal cord could be damages, but between L4 and L5 there are just nerve fibers that can be moved away.

Question 67

• Reflex arc

Answer 67

• Reflex arc: rapid automatic, involuntary reactions of muscles to a stimulus. They can be:
o Ipsilateral: both the receptor and effector organs are on the same side
o Contralateral: sensory impulses from a receptor organ cross over through the spinal cord to activate effector organs on the opposite limb.

Question 68

• Monosynaptic reflex

Answer 68

• Monosynaptic reflex: direct communication between sensory and motor neurpns ex: stretch reflex
o Stretch reflex: is a muscle contraction in response to stretching within the muscle. It is a monosynaptic reflex which provides automatic regulation of skeletal muscle length. When a muscle lengthens, the muscle spindle is stretched and its nerve activity increases

Question 69

• Muscle spindle

Answer 69

: monitors the length/stretch of a muscle. When a stimulus results in the stretching of a muscle, the muscle reflexively contract

Question 70

• Polysynaptic reflex

Answer 70

interneuron facilitates sensory-motor communication
o Withdrawal reflex: painful stimulus causes sensory information to be sent to the spinal cord.
 Interneurons receive the sensory info and stimulate the motor neurons to direct flexor muscles to contract.
 Simultaneously extensor muscles are inhibited so that the traumatized body part may be quickly withdrawn from the harmful stimuluation
o Golgi tendon reflex: nerve impulses signal interneurons in the spinal cord, which in turn inhibits the actions of the motor neurons.
 Golgi tendon organ: nerve endings located within tendons near a muscle-tendon junction. Monitor tension/force within tendons

Question 71

o Withdrawal reflex

Answer 71

a rype of polysynaptic reflex
painful stimulus causes sensory information to be sent to the spinal cord.
 Interneurons receive the sensory info and stimulate the motor neurons to direct flexor muscles to contract.
 Simultaneously extensor muscles are inhibited so that the traumatized body part may be quickly withdrawn from the harmful stimuluation

Question 72

golgi tendon reflex

Answer 72

type of polysynaptic reflex
o Golgi tendon reflex: nerve impulses signal interneurons in the spinal cord, which in turn inhibits the actions of the motor neurons.
 Golgi tendon organ: nerve endings located within tendons near a muscle-tendon junction. Monitor tension/force within tendons

Question 73

Functions of the integument

Answer 73

Functions of the integument:

1. Protection- from physical and chemical trauma, UV radiation, foreign matter
2. Water regulation- prevent water loss and excess water from getting into the body
3. Temperature regulation- if skin too warm, increase blood flow to the surface to cool blood as it returns to the body, also have sweat glands to cool skin and excrete excess things
4. Vitamin D synthesis- cells in integument need sunlight to trigger synthesis
5. Sensory perception
6. Excretion by secretion
7. Storage- almost 5% of blood volume is found in skin
8. Non-verbal communication- ex: color change of skin= don’t have oxygen so skin changes color- tells you you’re not breathing or you could faint or be going into shock or a bruise and have damaged cells in integument, or have jondus (yellow) because liver not functioning properly

Question 74

1. Explain the anatomy of the two primary layers, and their sublayers, of the integumentary system and the subcutaneous layer deep to it.

Answer 74

The cutaneous membrane is made of epidermis and the dermis.
o The epidermis is the outer layer of the skin.
o It is made up of stratified squamous epithelium.
o It can have 4-5 layers, depending on whether it is thick or thin.
o The innermost layer of the epidermis is called the stratum basale.
o The stratum spinosum is the next layer up, several cells thick
o The next layer is the stratum granulosum.
The stratum lucidum is the clear layer only found in thick skin of palms of hands and soles of feet.
o The stratum corneum is the most superficial layer of the skin

then there are accessory structures like hair, nails, exocrine glands
also has subcutaneous layer that isn’t really considered to be part fo the integument

dermis has papillary layer and reticular layer

Question 75

subcutaneous layer

Answer 75

• The subcutaneous layer is also referred to as the hypodermis and the superficial fascia. It is the fat of the body and is composed of areolar and adipose connective tissue.
o The functions of the subcutaneous layer are to protect the underlying structures, to store energy, and for thermal insulation (to help keep us warm).
o Is different from person to person and in males and females ex: pear type body shape and apple type body shape.

Question 76

cutaneous membrane

Answer 76

The cutaneous membrane is made of epidermis and the dermis.
o The epidermis is the outer layer of the skin.
o It is made up of stratified squamous epithelium.
o It can have 4-5 layers, depending on whether it is thick or thin.
o The innermost layer of the epidermis is called the stratum basale
->stratum spinosum->stratum granulosum->stratum lucidum (only in thick skin)-> stratum corneum

Question 77

stratum basale.

Answer 77

o The innermost layer of the epidermis is called the stratum basale.
• It is the deepest layer and is attached to the basal lamina, which separates the epidermis from the dermis.
• The stratum basale consists of basal cells, which undergo mitosis and produce new keratinocytes which gradually make their way up to the top of the skin and replace the keratinocytes that are shed.
• Scattered among the basal cells are melanocytes, which are pigment-producing cells. They inject their pigment, melanin, into the basal cells and the upper layers of the epidermis. Skin color does not depend on the number of melanocytes, but rather how long their legs are and therefore how much pigment they release into the skin.
• This layer also contains Merkel cells, which are the reason for skin areas that lack hair. They are responsible for touch, and therefore most common in areas such as the finger tips or lips where sensory perception is most acute.

Question 78

stratum spinosum

Answer 78

second layer after stratum basale
o The stratum spinosum is the next layer up, several cells thick
• and each time basal cells divide, they are pushed up to the stratum spinosum.
• There are keratinocytes in this layer,
• as well as melanocytes.
• There are also langerhans cells. These help trigger an immune response against cancer cells and pathogens that enter the epidermis
straum basale->spinosum->granulosum->lucidum (thick skin)->corneum (most superficial layer)

Question 79

stratum granulosum

Answer 79

straum basale->spinosum->granulosum->lucidum (thick skin)->corneum (most superficial layer)
• It consists of keratinocytes that have moved out of the stratum spinosum. Once they get to the stratum granulosum, they make proteins called keratohyalin and keratin, in large quantities.
• Most superficial layer of epidermis where all the cells still have nucleus
• Environmental factors influence rate at which keratinocytes synthesize keratohyalin and keratin- increase in friction against skin stimulates increased synthesis, forming callus

Question 80

stratum lucidum

Answer 80

is the clear layer only found in thick skin of palms of hands and soles of feet.
straum basale->spinosum->granulosum->lucidum (thick skin)->corneum (most superficial layer)

Question 81

stratum corneum

Answer 81

straum basale->spinosum->granulosum->lucidum (thick skin)->corneum (most superficial layer)
o The stratum corneum is the most superficial layer of the skin.
• It consists of flat, dead cells. These cells usually shed in groups, or sheets. And deeper layers are always protected by this layer of dead cells
• Dry so not good for microbe growth
• It is water resistant, but not waterproof.

Question 82

• Keratinocytes

Answer 82

Cells of epidermis:
• Keratinocytes:
o Provide protection- physical and mechanical
o Waterproof the skin
o Synthesize vitamin D
o Produce antibiotics and enzymes to detoxify the skin
o Are joined by desmosomes which provide stability
o Make up the majority of the epidermis
o The stratum corneum, granulosum and spinosum have lots of keratinocytes, ans as they make their way up from the stratum basale theu die and flatten out

Question 83

• Melanocytes

Answer 83

Cells of epidermis:
o Produce melanin- skin pihment
o Absorbs UV light and helps prevent DNA damage
o Tranfer of melanin to keratinocyte is via cell processes- have projections that help deliver the melanin into the keratinocyte
o There is no difference in the number of melanocytes in people of color- everyone has a similar number, what is diff is the level of melanin pumped into karatinocytes- in lighter skinned people, the lysozomes in keratincoytes digest the melanin while in people of color don’t have as many lysozomes so they have darker skin

Question 84

• Tactile Epithelial cells

Answer 84

• Tactile Epitherlial cells (merkel)
o Have receptors for touch
o Found in basal layer.

Question 85

• Dendritic cells

Answer 85

epithelial cells
o Aka langerhans cells
o Part of the immune system
o Take up foreign proteins via endocytosis and transport them to nearby lymph nodes to begin immun`e response

Question 86

dermis

Answer 86

o The dermis contains a papillary layer and a reticular layer.
• All of the dermis has a blood supply. The vasculature functions of the dermis are to supply nutrients to the avascular epidermis.
• The papillary layer diffuses nutrients to the endodermis, as it has nipple-like projections called papillae that have an increased surface area, making diffusion easier.
 It is also important in controlling body temperature.
 The upper layer of the dermis is called the papillary layer. It is composed of areolar connective tissue. The dermal papillae and the epidermal ridges interlock because dermal papillae contain capillaries. Finger ridges are folds of the epidermis and dermis on the fingers, palms, and soles. Their function is to increase friction for grasping things
• There are also nerves in the dermis. They have an important function in tactile receptors, controlling blood flow, and controlling glandular secretion.
• The reticular layer of the dermis is composed of dense irregular connective tissue with bundles of collagen fibers.
 The dense irregular connective tissue is good at reducing forces, and the collagen fibers line up parallel to each other and make cleavage lines.
 If you cut yourself parallel to one of the cleavage lines, it closes up. However, if you cut yourself perpendicular to them, they leave a scar. Striae are stretch marks that result from the skin being overstretched, causing collagen fibers to tear.

Question 87

papillary layer

Answer 87

• The papillary layer diffuses nutrients to the endodermis, as it has nipple-like projections called papillae that have an increased surface area, making diffusion easier.
 It is also important in controlling body temperature.
 The upper layer of the dermis is called the papillary layer. It is composed of areolar connective tissue. The dermal papillae and the epidermal ridges interlock because dermal papillae contain capillaries. Finger ridges are folds of the epidermis and dermis on the fingers, palms, and soles. Their function is to increase friction for grasping things

Question 88

reticular layer

Answer 88

• The reticular layer of the dermis is composed of dense irregular connective tissue with bundles of collagen fibers.
 The dense irregular connective tissue is good at reducing forces, and the collagen fibers line up parallel to each other and make cleavage lines.
 If you cut yourself parallel to one of the cleavage lines, it closes up. However, if you cut yourself perpendicular to them, they leave a scar. Striae are stretch marks that result from the skin being overstretched, causing collagen fibers to tear.

Question 89

basal cell carcinoma
squamous cell carcinoma
malignant melanoma

Answer 89

• basal cell carcinoma- cancer of the stratum basale, most common, least dangerous, can be taken care of with surgery.
• squamous cell carcinoma- Cancer of the stratum spinosum, may metasotize, occurs in scalp, ears, lips where usually exposed to sun, more aggressive than basal cell carcinoma
• malignant melanoma- Cancer of the melanocytes, most aggressice and deadly skin cancer, metastosizes and spreads through body quickly
be conscious of moles/discoloration on body if:
• they are asymmetrical
• have irregular borders
• are not a unifrom color
• larger than 6.. or growing
• grow in size, shape, color, feel, or bleed

Question 90

5. Describe the structures that are derived from the dermis.

Answer 90

Nails are a modification of the stratum corneum. They are there to protect the distal fingertips.
Sweat glands are located on the dermis, and they are very abundant exocrine glands. We sweat for thermoregulation, secretion, and protection.
Hairs are columns of keratinocytes that exist for protection, heat retention, and sensory reception. Arrector pili muscles attach to the hair root. Goosebumps are a contraction of the arrector pili muscles.
Sebaceous glands secrete oily sebum, which softens and lubricates the hair and skin.

Question 91

6. Explain how skin changes with aging.

Answer 91

As you get older, your skin gets thinner because of a decrease in activity of stratum basale cells. You become more prone to injury and infections.
Langerhans cells start functioning below optimal levels.
You get a decrease in vitamin D production, leading to muscle and bony weaknesses.
Melanocyte activity decreases so you become pallor.
Decreased sebaceous gland activity leads to drier skin. There is reduced sweat gland production and reduced blood supply to the dermis so we can’t cool off as well.
There are decreased number of collagen fibers and loss of elasticity in elastic fibers.
UV exposure accelerates aging process.

Question 92

7. Differentiate between the sensory receptors in the skin and summarize the pathways the signals from specific receptors would take through the spinal cord

Answer 92

1. Exteroreceptors:
   • are located on the surface of the skin or on mucous membranes.
   • They tell us about pressure, pain, etc.
   • 3 of these kinds of receptors are open-ended (unencapsulated), while 3 have Schwann cells around them (encapsulated), but are not myelinated.
   >free nerve ending
   >root hair plexs
   >tactile (merkel) disc

encapsulated
>tactile (meissner) corpuscle
>lamellated
>bulbous corpuscles

Question 93

8. Unencapsulated exterorreceptors in skin

Answer 93

o free nerve ending: This is found in the papillary layer of the dermis and the deep epidermis. Its primary job is to detect pain and temperature.
o Root hair plexuses: unencapsulated, surround hair follicles in the dermis. They are responsible for the movement of hairs, and respond to light touch
o Tactile (Merkel) discs: are associated with the tactile cells in the stratum basale of the epidermis. They respond to light touch.

• Spinal cord pathways:
o Dorsal column medial lemniscus pathway (light touch is what this pathway deals with) So have tactile (merkle’s disc), tactile (meissner’s) disc and root hair plexus here
o Anterolateral (spinothalamic pathway) deals with pain so the bulbous and free nerve endings are in this category.
o Lamellated no classification since deal with pressure and vibration

Question 94

• Encapsulated exterpreceptors in skin

Answer 94

o One receptor is the Tactile (Meissner) corpuscle. These are found in some dermal papillae. They respond to light touch, texture, shape, and low frequency vibration.
o Lamellated (Pacinian) corpuscles are found in the dermis, subcutaneous tissue, synovial membranes, and some viscera. These can’t be classified because they respond to deep pressure and high-frequency vibrations.
o Bulbous (Ruffini) corpuscles are found the dermis and subcutaneous layer and respond to continuous deep pressure, force/motion and skin distortion.
• Spinal cord pathways:
o Dorsal column medial lemniscus pathway (light touch is what this pathway deals with) So have tactile (merkle’s disc), tactile (meissner’s) disc and root hair plexus here
o Anterolateral (spinothalamic pathway) deals with pain so the bulbous and free nerve endings are in this category.
o Lamellated no classification since deal with pressure and vibration

Question 95

• Dermatomes

Answer 95

• Dermatomes are specific areas of the skin supplied by a single spinal nerve, and are how a nerve root is displayed on the skin.

Question 96

1. Compare and contrast the different kinds of cartilage

Answer 96

Hyaline cartilage consists of closely packed collagen fibers. It is located between the tips of the ribs, bones of the sternum, along the passageway of the respiratory tract, and covers the bone surface at synovial joints. The function of hyaline cartilage is to provide stiff but somewhat flexible support, and to reduce friction between opposing surface (i.e. synovial joints).
Elastic cartilage is made up of elastic fibers, which make it very flexible. Its main function if to provide support, but tolerate distortion and return to its original shape. It is located at the auricle of the external ear, the epiglottis, and the auditory canal.
Fibrous cartilage consists of predominantly collagen fibers. It is located at areas of high stress, such as the pads of the knee, between pubic bones, and between intervertebral discs. Its function is to reduce compression, prevent bone-to-bone contact, and limit relative movement.

Question 97

1. Explain the two methods of cartilage growth.

Answer 97

The first method of cartilage growth is appositional growth. In this method, cartilage grows by adding onto its existing surface. This causes an increase in diameter. Stem cells along the inner layer of the perichondrium continually divide. The innermost cells differentiate into chondroblasts, which produce cartilage matrix. Once they are completely surrounded by matrix, they differentiate into chondrocytes within lacunae.
Interstitial cartilage growth occurs from the inside of cartilage, much like a balloon being inflated. The end result is an increase in length and density. A chondrocyte in a lacunae is stimulated to divide. The division results in a two daughter cells, or two chondroblasts. The chondroblasts secrete new cartilage matrix, pushing each other apart. They then become separated and become two different chondrocytes in lacunae. After, they continue to secrete their own cartilage matrix.

Question 98

3. Describe characteristics of the two different types of bones.

Answer 98

While compact bone consists of osteons, spongy bone does not. Compact bone contains blood vessels trapped within the matrix, while spongy bone does not contain any blood vessels. Compact bone is dense and solid, while spongy bone forms an open network of struts and plates (trabeculae). Compact bone forms the walls of bone, while spongy bone lines the medullary cavity, which consists of bone marrow.

Question 99

4. Describe the functions of bone

Answer 99

To support the weight of the body, to allow movement, to protect vital organs, to store minerals to be released into the bloodstream, for hematopoiesis (blood cell production) from red bone marrow, and for energy metabolism (osteoblasts secrete hormones that have effects on blood sugar levels).

Question 100

Intramembranous ossification

Answer 100

Intramembranous ossification begins during week 8 of development and consists of bones forming from a membrane of connective tissue. It results in flat bones, such as the skull. It starts when blood vessels come into the mesenchymal cells (stem cells of connective tissue) causing vascularization, and release a signal for them to turn into osteoblasts. The osteoblasts secrete a matrix that create osetoids which mineralize through the crystalization of calcium salts into ossification centers. These ossification centers extend and create bony spicules. As the bone continues to grow, blood vessels get trapped inside it as spicules grow. Continued deposition of bone by osteoblasts creates a bony plate that is perofrated by blood vessels, and adjacent plates fuse together and form a complex structure. In the end, this forms spongy bone.

Question 101

7. Explain how bone architecture can change with age.

Answer 101

As you get older, bones lose their mass and density. Osteoarthritis occurs when aging and stress result in decreased chondrocyte ability to maintain and repair its matrix. Osteopenia occurs when bone mineral density is lower than normal. Osteoporosis occurs when the rate of bone breakdown and resorption by osteoclasts is greater than production by osteoblasts.

Question 102

7. Explain how bone architecture can change with age.

Answer 102

As you get older, bones lose their mass and density. Osteoarthritis occurs when aging and stress result in decreased chondrocyte ability to maintain and repair its matrix. Osteopenia occurs when bone mineral density is lower than normal. Osteoporosis occurs when the rate of bone breakdown and resorption by osteoclasts is greater than production by osteoblasts.

Question 103

Endochondral ossification

Answer 103

Endochondral ossification occurs between the 8-12th week of development, and forms all bones except for flat bones. It involves turning hyaline cartilage into bone. It starts with a hyaline cartilage model. As cartilage increases in size, chondrocytes increase in size and surrounding matrix calcifys, Chondrocytes die off because they are not getting nutrients via diffusion. Blood vessels invade hyaline cartilage and cells differentiate into osteoblasts which at the periphery lay down a superficial layer of bone called a bone collar. Blood supply to the periosteum increases and cappillaries and osteoblasts get into the heart of the cartilage. These osteoblasts produce spongy bone by invading the space left by the calicified chondrocytes and replace it with spongy bone forming the primary ossification center. The primary ossification center undergoes remodeling and eventually produces the medullary cavity. The same process repeats at the secondary ossification centers in the epiphyses. The epiphyses flls with spongy bone, and the epiphysis and disphysis are separated by a thin layer of articular cartilage called the epiphyseal cartilage/plate. The epiphyseal cartilage (aka epiphyseal plate) separates epiphysis from diaphysis. It also regulates the length of the bone. chondrocytes on the epiphyseal side continue to divide and grow, and the chondrocytes on the side of the diaphysis die. Osteoblasts migrate to epiphyses and lie down bone to increase length.

Question 104

Endochondral ossification

Answer 104

Axial = skull, spinal column and ribs. Appendicular = upper and lower limbs, pectoral girdle- connects upper limbs to rest of body, pelvic girdle – connects lower limbs to rest of body

Question 105

2. Describe how structure governs function with joints.

Answer 105

More stable structure means less mobility, less stable structure means more mobility.
Other factors influencing joint stability:
• Articular surfaces: shape influences movements possible and stability, ex: shoulder vs hip- are both diff types of ball and socket joints and can do similar things but hip is a deeper/stronger joint so can’t move as much, much more stable
• Ligaments: capsules and ligaments prevent excessive motions. The more ligaments, usually the stronger and more stable the joint
• Muscle tone: helps stabilize joints by keeping tensions on tendons

Question 106

• Immobile joints

Answer 106

• Immobile joints: Don’t really move, and shouldn’t move.

1. Fibrous- bones joined by dense regular CT, no joint cavities.
2. Cartilaginous- bones attached by cartilage, no joint cavities.

Question 107

• Synovial joints

Answer 107

mobile joints, richly supplied with sensory nerves to detect pain and most monitor how much the capsule is being stretched/how much the joint is moving Freely mobile diarthroses, articulating bones separated by a fluid filled joint cavity. General anatomy:
Articular capsule- is the fibruous joint capsule
Joint cavity- full of fluid, inbetween bones
Synovial fluid-
Articular cartilage- lines ends of bones
Articular cartilage- hyaline cartilage, reduces friction and acts as a shock absorber. Articular capsule- has 2 layers,
-outer fibrous layer made of dense regular connective tissue to strengthen for stability.
-Inner synovial membrane that secrete synovial fluid which lubricates joint and decreases friction, and abs shock, and has macrophages to fight small microbes and infections
Joint cavity- contains synovial fluid that lubricates to allow for frictionless movement, absorb shock, and remove waste products

Ligaments- can be inside or outside joints
Nerves and blood vessels- very vascularized and have neurological structures in capsule and joint Have a rich blood supply which supply nutrients to the joint o	Ligaments- connect bone to bone, made of dense regular connective tissue, strengthen and reinforce capsule o	Articular discs- present in some synovial joins, occur with articulating bones of different shapes

Question 108

Synovial joint anatomy
-Bursae
tendon sheath
fat pads

Answer 108

• Synovial joint anatomy - accessory structures: reduce friction and fill spaces
o Bursae: sac containing synovial fluid, cellophane like bag with synovial fluid to decrease friction in joints, can get ruptured
o Tendon sheaths: elongated bursae around tendons, decreases friction on tendon as it moves
o Fat pads: packing material, also provide some protection, fills space around joint

Question 109

5. Describe movements around joints with respect to their planes and joints.

Answer 109

coronal plane (divides body into front and back)- anteroposterior axis: so bending forward and backward
sagittal plane (divides body into left and right)- transverse axis 
transverse plane(divides body into top and bottom)- vertical axis

movement in a joint takes place in a plane, about an axis. The axis is perpendicular to the plant the movement occurs in.

Question 110

1. Describe the three layers that make up the blood vessels.

Answer 110

Arteries and veins have three layers: the outer adventitia, the middle media, and the inner intima.

Question 111

outer adventitia

Answer 111

The outer adventitia forms is a thick connective tissue that is made up of mostly collagen fibers with scattered elastic fibers, that surround the entire blood vessel (in veins this layer is usually thicker than the media). The fibers of the outer adventitia usually blend in with surrounding tissue, which stabilizes the blood vessel.

Question 112

The media

Answer 112

The media is a concentric layer of smooth muscle supported by a framework of loose connective tissue. Vasoconstriction is when stimulation by the sympathetic branch of the autonomic nervous system causes the smooth muscle to contract, which reduces the lumen diameter of the blood vessel. Vasodilation is when the smooth muscles relax and the lumen diameter increases. These smooth muscles also contract and relax in response to local stimuli such as changes in Ph, pCO2 etc.
(collagen fibers bind the media to both the intima and adventitia.

Question 113

The intima

Answer 113

The intima, is the inner most lining of blood vessels, makes up the endothelial lining of the lumen with an underlying layer of connective tissue, with varying amounts of elastic fiber. The combination of elastic and muscular fibers are important in giving the veins and arteries strength

Question 114

vessel walls arteries vs veins

Answer 114

Arteries have thicker walls than veins- they contain more smooth muscle and elastic fibers than veins- these contractile and elastic components resist pressure made by heart as it forces blood into circuit

Question 115

vessel lumen- arteries vs veins

Answer 115

Walls of artery contract, contricting lumen so when dissected, the artery walls are thick and stronger and retain their shape
Dissected veins collapse

Question 116

Vessel lining arteries vs veins

Answer 116

Endothelial lining of an artery can’t contract so when an artery constricts, its endothelium forms so sectioned arteries have a pleated appearance. Veins lack these folds

Question 117

valves- veins vs arteires

Answer 117

arteries-no valves

veins-yes valves

Question 118

arteries

Answer 118

The three types of arteries are elastic arteries, muscular arteries, and arterioles
Elastic arteries have the largest diameter of all the arteries, as they transport a large amount of blood away from the heart ex: pulmonary artery and aorta. The media of an elastic artery is composed of many elastic fibers and very few smooth muscle cells. This allows it to tolerate the pressure changes of the cardiac cycle. (smooth muscle cells present in the media of elastic arteries do not contract in response to sympathetic or local stimulation).

Muscular arteries transport blood to the skeletal muscles and internal organs. Their media is thicker and contains more smooth muscle cells than those of elastic arteries. The sympathetic division of the ANS and local stimulation control the luminal diameter of muscular arteries. by constricting or relaxing the smooth muscle in the media, the autonomic nervous system regulates blood flow to each organ independently.

Arterioles are considerably smaller than elastic and muscular arteries. Arterioles control blood flow between arteries and capillaries

Question 119

Elastic arteries

Answer 119

have the largest diameter of all the arteries, as they transport a large amount of blood away from the heart ex: pulmonary artery and aorta. The media of an elastic artery is composed of many elastic fibers and very few smooth muscle cells. This allows it to tolerate the pressure changes of the cardiac cycle. (smooth muscle cells present in the media of elastic arteries do not contract in response to sympathetic or local stimulation).

Question 120

Muscular arteries

Answer 120

transport blood to the skeletal muscles and internal organs. Their media is thicker and contains more smooth muscle cells than those of elastic arteries. The sympathetic division of the ANS and local stimulation control the luminal diameter of muscular arteries. by constricting or relaxing the smooth muscle in the media, the autonomic nervous system regulates blood flow to each organ independently

Question 121

Arterioles

Answer 121

are considerably smaller than elastic and muscular arteries. Arterioles control blood flow between arteries and capillaries

Question 122

Capillaries

Answer 122

Capillaries are the smallest and most delicate blood vessels. They are the only blood vessels whose walls allow exchange of nutrients between blood and interstitial fluid. Because their walls are thin, diffusion distances are short and exchange between blood and interstitial fluids occurs quickly.
There are three types of capillaries: continuous, fenestrated, and sinusoids.
-Continuous capillaries are the most common and have cracks that allow the exchange of O2, CO2, and nutrients. Have the most control for what is going to leak out.
-Fenestrated have little pores that allow larger molecules than continuous capillaries- allow molecules as large as peptides and small proteins to pass through
-Sinusoids have very large pores that allow big things to go through, and even sometimes allow things to go through that aren’t supposed to. Are flattened and irregularly shaped. They permit the free exchange of water and solutes such as plasma proteins between blood and interstitial fluid. They are found in the spleen and bone marrow, and their large holes slow down blood flow and allows many things to exchange.

Question 123

Continuous capillaries

Answer 123

Continuous capillaries are the most common and have cracks that allow the exchange of O2, CO2, and nutrients. Have the most control for what is going to leak out.

Question 124

Fenestrated capillaries

Answer 124

Fenestrated have little pores that allow larger molecules than continuous capillaries- allow molecules as large as peptides and small proteins to pass through

Question 125

Sinusoids capillaries

Answer 125

Sinusoids have very large pores that allow big things to go through, and even sometimes allow things to go through that aren’t supposed to. Are flattened and irregularly shaped. They permit the free exchange of water and solutes such as plasma proteins between blood and interstitial fluid. They are found in the spleen and bone marrow, and their large holes slow down blood flow and allows many things to exchange.

Question 126

veins

Answer 126

Veins take all the blood from tissues and organs and send it back to the heart. Their walls are thinner than the walls of arteries because the blood pressure is lower in them. But they do have larger luminal diameters than thei corresponding arteries.
Venules, which collect blood from capillaries, are the smallest veins.
Medium-sized veins make up the majority of veins, and are the deepest veins. They are found side by side muscular arteries and take blood back from muscles and tissues. They have venous valves, which prevent the backflow of blood when it has to travel against gravity.
Large veins are the third type of vein, include the superior and inferior venae cavae. Large veins do not have valves but changes in pressure within body cavities help move blood toward the heart.

Question 127

3. Explain how blood returns to the heart despite low blood pressure in veins

Answer 127

There are three mechanisms for this: muscle pumps, respiratory pumps, and valves.
Muscle pumps are present in the skeletal muscles near veins, and when the muscle contracts, the closed-portion of the vein pushes blood up.
The respiratory pump, or your lungs, expands when you take a deep breath, causing the pressure to decrease and fluid to flow in. When you breath out, the pressure increases and fluid flows out.
Valves are inside the vein and prevent the backflow of blood. Nonfunctional valves are called varicose veins, and are most common in the superficial veins of the lower limbs. These valves flip back and cause blood to pool down and not come back up easily.

Question 128

4. Explain the importance of collateral circulation

Answer 128

Collateral circulation is important because it provides alternative pathways for blood to get to a region of the body when a blood vessel is blocked off. Arteriovenous anastomoses connect arteries directly with veins. Arterioarterial anastomoses provide collateral circulation to many organs and body regions.

Question 129

5. Describe the components of blood.

Answer 129

The functions of blood are transport of O2, CO2, nutrients, waste and hormones, regulation of pH electrolytes and body temperature, and protection using leukocytes and clotting.

Blood consists of plasma which is the least dense component of blood about 55%, a buffy coat which is a middle layer ocntaining leukocytes and platelets (about 1%) and erythrocytes about 44%.

Plasma is made up mostly of water (90%). It also consists of electrolytes, nutrients, organic compounds, etc. Overall, your plasma reflects your metabolic activity and therefore can be an important diagnostic tool. Plasma can be donated much more often than blood because plasma can regenerate much faster, as it is mostly water. You can drink lots of water to regenerate your plasma, but when you donate blood, you lose cells and have to wait for those to regenerate on their own.
Platelets are the smallest circulating formed elements, as they are just cell fragments. They are important because they form clots. When you cut yourself, your platelets send fibers that allow blood to stop moving and therefore form a clot. With a lifespan of about 8 days, platelets don’t live very long.
Erythrocytes are red blood cells. They make up 99% of blood cells (although have no nucleus or organelles). They have biconcave structure that gives it a big surface area, allowing increased O2 and CO2 transport. They contain a protein called hemoglobin, which carries oxygen and carbon dioxide in the blood. Their biconcave shape also allows them to stretch and bend in order to get through tight blood vessels. They have a 120 day lifespan.

Question 130

leukocytes

Answer 130

The function of leukocytes (white blood cells) is for defense. They circulate in the bloodstream, but most are found in loose connective tissue. There are two categories of leukocytes: granular and agranular.

• Granular leukocytes- non-specific destruction of antigens, consist of neutrophils, eosinophils, and basophils.
• Agranular leukocytes- one non=specific destroyer and one antigen-specific immune cell types, consist of monocytes and lymphocytes.

Question 131

Neutrophils

Answer 131

Neutrophils make up the majority of leukocytes. Neutrophils are active phagocytes and attack and engulf bacteria and debris in tissues
granular

Question 132

Eosinophils

Answer 132

granular
Eosinophils make up 4-5% of leukocytes. They attack objects that are coded with antibodies. When you’re having an allergic reaction, the number of eosinophils increases dramatically. Important in fighting parasitic infections. They release enzymes that reduce inflammation

Question 133

basophils

Answer 133

granular
Basophils make up less than 1% of the leukocyte population. They go to a site of injury in epithelial tissues to release granules in the interstitial fluid. These granules have histamine, which dilates the blood vessels, and heparin, which prevents blood clotting.
produce inflammation

Question 134

monocytes

Answer 134

agranular
Monocytes arrive at an injury site shortly after neutrophils do to phagocytize pathogens and debris. While the do this, they release a chemicals that attract other monocytes to come help.

Question 135

lymphocytes

Answer 135

agranular
Lymphocytes are the primary cell of the lymphatic system and they are responsible for specific immunity, or the ability for the body to attack invading pathogens or foreign proteins on an individual basis.

Question 136

6. Explain blood types, blood donor compatibility, and the Rh factor.

Answer 136

Type A blood cells contain surface antigen A. This means that the plasma of someone with type A blood contains anti-B antibodies, which attack type B surface antigens. Type B blood has the surface antigen B. Someone with type B blood has plasma with anti-A antibodies that attack type A surface antigens. Type AB blood contains both surface antigens A and B. This means that your plasma does not have any antibodies, and you can accept both A and B blood. Type O blood has neither A nor B surface antigens. This means that your plasma contains both anti-A and anti-B antibodies, and can therefore only accept type O blood. Type O blood is the universal donor, and type AB blood is the universal acceptor. All blood is either positive or negative. Positive blood can accept negative blood, but negative blood cannot accept positive blood. During pregnancy, an Rh negative mother could have a baby with Rh positive blood. Because this blood is in her system, she could develop antibodies to Rh + blood. If her next baby has Rh + blood, those antibodies can cross the placenta and could destroy the red blood cells of the fetus.

Question 137

7. Explain the structure of the lymphatic vessels.

Answer 137

Lymphatic capillaries are close-ended tubes that are interspersed around blood capillary beds. They receive fluid from connective tissue, are highly permeable so things get in very easily. When a capillary leaks fluid into surrounding tissue, it needs to get it back into the blood, so the lymphatic system does this. Lymphatic capillaries are highly permeable, and overlapping endothelial cells on the inside of their lumen act as one-way valves.
Lymphatic capillaries are the first to receive lymph.
Collecting lymphatic vessels collect fluid from loose connective tissue and return it to the bloodstream via the veins.
Lymph trunks collect lymph from collecting vessels.
Lymph ducts empty fluid into the veins of the neck.
There are 2 lymphatic ducts where fluid enters back in the bloodstream. The right drains a smaller portion of the body-the right side of the head and neck, right upper limb and the right side of the thorax
the thoracic drains the majority of the body- it begins just inferior to the diaphram, begins as a saclike structure called the cisterna chyli and collects lymph from most of the body.

Lymphedema is an accumulation of lymphatic fluid due to lymphatic drainage issues or lymphatic failure. It creates swelling and creates an increased risk of infection due to an increased surface area.

Question 138

Lymphatic capillaries vs, vascular cappilaries

Answer 138

Lymphatic capillaries are larger in diameter
Lymp capillaries have thinner walls
Lymp capillaries have an irregular outline
Lymp capillaries have anchoring

Question 139

1. Identify the functions of the lymphatic system

Answer 139

The functions of the lymphatic system are: To bring fluid that spills out of blood into loose connective tissue back to the blood. As an alternate route of transport for hormones, nutrients, and wastes - it’s not just blood that transports these things. To produce, mature, and distribute lymphocytes. To work alongside the immune system to generate an immune response against antigens in the interstitial fluid. Primary lymphatic structures are organs that don’t have a role in fighting off infections, but instead produce and mature lymphocytes. This includes the thymus and red bone marrow. Secondary lymphatic structures are organs that work as the front line of defense and fight off foreign substances. This includes the MALT (mucosa-associated lymphoid tissue), tonsils, appendix, aggregated nodules, lymph nodes, and the spleen.

Question 140

2. Describe the relationship between the lymphatic system and immune function

Answer 140

The lymphatic system works with the immune system to fight off bacteria, foreign substances, etc. Lymphocytes are the primary cells of the lymphatic system. They respond to bacteria, cancer cells, and other foreign substances. They travel throughout the lymphatic vessels and throughout blood vessels. There are three types of lymphocytes: T cells, B cells, and NK cells. T cells are thymus-dependent cells. They produce cell-mediated immunity. B cells are bone marrow-derived cells. They produce antibodies that attack foreign substances. Nk cells are natural killer cells. They directly kill any foreign cell.

Question 141

3. Predict the consequences of the anatomy of the lymphatic system (i.e. cancer spread) and lymphatic system dysfunctions

Answer 141

The lymphatic system allows large molecules to enter it so it can do its job. However, it doesn’t exclude things like cancer cells. Cancer cells can become lodged within lymph nodes, and lymphoma is the cancerous growth of a lymph node. Lymph nodes in the breasts and testicles should be checked often for cancer, because they have lymph nodes very close by

Question 142

4. Describe the organs of the lymphatic system and their functions in the immune system

Answer 142

Lymphatic organs are separated from surrounding tissue by a fibrous capsule. This includes lymph nodes, the thymus gland, and the spleen. The function of the lymph nodes is to attack any foreign substance in the lymphatic vessels, as lymph travels through lymph node. When there is an infection, the lymph nodes get bigger because they are trying to fight it off. The lymph comes into the lymph nodes through afferent vessels and leaves through efferent vessels. The thymus is located superior and anterior to the heart. Its function is to produce T cells, which participate in cell-mediated immunity. The function of the spleen is the find old/damaged cells and break them down and to produce/release lymphocytes to start an immune response. It is located in the upper left quadrant. The spleen is highly vascularized so that blood can come into the spleen in order to kill the old and/or damaged cells. This makes up the red pulp of the spleen. The white pulp consists of lymphoid tissue, lymphocytes, and macrophages

Question 143

5. List the major endocrine organs, describe their locations, and list their main function

Answer 143

The endocrine system sends hormones into the bloodstream. For this reason, endocrine glands are highly vascularized. The hormones that it releases can only affect target cells, or cells that have receptors specifically for that hormone.

The hypothalamus is like the control center for the endocrine system. It is located on the inferior part of the brain. It controls the release of regulatory hormones from the anterior pituitary gland and secretes specific hormones for the posterior pituitary gland. The pituitary gland is inferior to the hypothalamus. It is attached to the hypothalamus by the infundibulum.
The anterior pituitary gland is also called the adenohypophysis. Releasing and inhibitory hormones are released from the hypothalamus to the anterior pituitary gland. They get there by going into the capillaries, going to veins, going to the next set of capillaries, and then being released. These hormones enter back into the circulation through the hypophyseal artery. This circle is called the hypothalamo-hypophyseal portal system. The posterior pituitary is also called the neurohypophysis. Unlike the anterior pituitary, it does not have a portal system. Instead, there is a neural connection between it and the hypothalamus. The axons make up the hypothalamohypophyseal tract. It stores and releases the hormones made in the hypothalamus. The thyroid gland is the largest endocrine gland. It is responsible for the metabolism, for osteoblast activity, and for calcitonin release (this reduces the blood calcium and encourages bone deposition). The parathyroid glands are located on the posterior of the thyroid. They release parathyroid hormone, which increases osteoclast activity, and therefore increases blood calcium. The adrenal glands paired pyramid-shaped glands on the superior border of the kidneys. It is made up of the adrenal cortex, which has 3 different layers, which release three different hormones. The adrenal medulla releases epinephrine and norepinephrine, which are related to the fight-or-flight response and help the body cope with danger, stress, and terror. The pancreas has both exocrine and endocrine functions. Pancreatic islets (islets of Langerhans) are hormones of islet cells closely regulated by blood glucose levels.

Question 144

endorcrine systen versus lymph system

Answer 144

communication: nervous-neurotransmitters released into synaptic cleft
endo: hormones released into blood

target
neuro-other neurons, muscle cells, glands
endo- any cell in the body with a receptor for that hormone

response time
neuro-rapid
endo-slow

range of effect
neuro-localized, specific effects
endo-widespread effects throughout the body

response duration
neuro-short (miliseconds)
endi-long lasting (minutes to days to weeks)

Question 145

hypothalamus

Answer 145

The hypothalamus is like the control center for the endocrine system. It is located on the inferior part of the brain. It controls the release of regulatory hormones from the anterior pituitary gland and secretes specific hormones for the posterior pituitary gland. The pituitary gland is inferior to the hypothalamus. It is attached to the hypothalamus by the infundibulum.

Question 146

pituitary gland

Answer 146

The pituitary gland is inferior to the hypothalamus. It is attached to the hypothalamus by the infundibulum

Question 147

anterior pituitary gland

Answer 147

The anterior pituitary gland is also called the adenohypophysis. Releasing and inhibitory hormones are released from the hypothalamus to the anterior pituitary gland. They get there by going into the capillaries, going to veins, going to the next set of capillaries, and then being released. These hormones enter back into the circulation through the hypophyseal artery. This circle is called the hypothalamo-hypophyseal portal system.

Question 148

posterior pituitary

Answer 148

The posterior pituitary is also called the neurohypophysis. Unlike the anterior pituitary, it does not have a portal system. Instead, there is a neural connection between it and the hypothalamus. The axons make up the hypothalamohypophyseal tract. It stores and releases the hormones made in the hypothalamus

Question 149

thyroid gland

Answer 149

The thyroid gland is the largest endocrine gland. It is responsible for the metabolism, for osteoblast activity, and for calcitonin release (this reduces the blood calcium and encourages bone deposition). Thyroid hormone increases metabolism and osteoblast activity.

Question 150

parathyroid glands

Answer 150

The parathyroid glands are located on the posterior of the thyroid. They release parathyroid hormone, which increases osteoclast activity, and therefore increases blood calcium

Question 151

adrenal glands

Answer 151

The adrenal glands paired pyramid-shaped glands on the superior border of the kidneys. It is made up of the adrenal cortex, which has 3 different layers, which release three different hormones. The adrenal medulla releases epinephrine and norepinephrine, which are related to the fight-or-flight response and help the body cope with danger, stress, and terror

Question 152

pancreas

Answer 152

The pancreas has both exocrine and endocrine functions. Pancreatic islets (islets of Langerhans) are hormones of islet cells closely regulated by blood glucose levels. Alpha cells of pancrease secrete glucagon (works to raise the concentration of glucose and fatty acids in the bloodstream) beta cells secrete insulin.

Question 153

6. Describe how tissue, muscles, and the endocrine system change with aging.

Answer 153

Tissue: thinner epithelia, collagen decreases, bones, muscles, nervous tissue begin atrophy, poor nutrition and poor circulation lead to poor health issues.
Muscle changes with aging: amount of connective tissue increases in muscles, decreased number of muscle fibers, loss of muscle mass.
Endocrine: endocrine organs operate effectively until old age, slight age-related changes in the anterior pituitary and thyroid, no changes in the adrenal gland, changes in reproductive hormones and growth hormones.