Anatomy Test 9 (Muscular System 5 + Nervous Tissue

What do the lower limb muscles function in?

Stability, locomotion, and maintenance of posture

What do the majority of the muscles that move the femur have a proximal attachment on?

The pelvic girdle

What do the majority of the muscles that move the thigh bone have a distal attachment on?

The femur

What are the psoas major and illiacus known as?

The iliopsoas

What is the most powerful flexor muscle of the thigh? Why is it important?

The iliopsoas is the most powerful muscle in the thigh therefore it is important walking, running, and standing

How many gluteal muscles are there? What are they?

3-

1. Gluteus maximus

2. Gluteus Medius

3. Gluteus minimus

What is the form of the gluteus Maximus?

Quadrilateral form

What does the attachment of the gluteus Maximus of the iliotibial tract do?

It helps hold (lock) the knee in extension

What muscle is a common site for intramuscular injection?

The gluteus medius

What is the smallest of the gluteal muscles?

The gluteus minimus

What type of muscle is the tensor fascia latae?

It is a fusiform muscle

Where is the tensor fascia latae located?

On the lateral surface of the proximal thigh

What is the fascia lata?

It is the dense connective tissue fascia that encircles the entire thigh

How is the IT band formed?

It is formed because the tensor fascia latae muscle attaches to the underside of the fascia on the lateral side along with the gluteus Maximus muscle. At this junction of these muscles the fascia ends form the iliotibial tract (IT band)

What is the IT band?

A strong band of connective tissue that spans the lateral aspect of the thigh from the ilium to the tibia

Approximately how wide is the IT band?

Approximately 3 fingers wide

What are the muscles that are deep to the gluteus Maximus and function as lateral rotators of the femur at the hip joint?

The pisiformis and quadratus femoris

What muscle has a relationship with the sciatic nerve?

The pisiformis

What separates the muscles of the thigh that act on the femur, tibia, and fibula?

Deep fascia

What do the adductor longus, adductor brevis, and adductor magnus do when the foot is on the ground? Off the ground?

When the foot is on the ground, they medially rotate the thigh, but when the foot is off the ground they laterally rotate the thigh

What is the adductor hiatus?

The space formed by the separation of the distal tendons of the adductor magnus just superior to the medial condyle of the femur

What is the femoral triangle?

A space at the junction between the trunk and the lower limb

What is the base of the femoral triangle formed by?

Superiorly by the inguinal ligament, medially by the lateral border of the adductor longus, and laterally by the medial border of the sartorius

What is the apex of the femoral triangle formed by?

The apex is formed by the crossing of the adductor longus by the sartorius

What are the contents of the femoral triangle from lateral to medial?

The femoral nerve and its branches, the femoral artery and several of its branches, the femoral vein and its proximal tributaries, and the deep inguinal lymph nodes

What is the femoral artery?

It is easily accessible within the triangle and is the site for insertion of catheters that may extend into the aorta and ultimately into the coronary vessels of the heart

What does the anterior (extensor) compartment of the thigh contain?

The sartorius and the quadriceps femoris

What is the largest muscles in the body?

The quadriceps femoris

Whaat are the 4 quadriceps femoris muscles?

1. The rectus femoris

2. The vastus lateralis

3. The vastus medialis

4. The vastus intermedius

What aspect of the thigh is the rectus femoris on?

The anterior aspect of the thigh 

What aspect of the thigh is the vastus lateralis on?

The lateral aspect of the thigh

What aspect of the thigh is the vastus medialis on?

The medial aspect of the thigh

Where is the vastus intermedius located?

It is located deep to the rectus femoris between the vastus lateralis and the vastus medialis

What common tendon of the 4 quadriceps muscle attaches to the patella?

The quadriceps tendon

How does the quadriceps tendon continue down below the patella?

It continues down as the patellar ligament

What muscle helps sitting Cris-cross?

The sartorius

What is the sartorius also known as?

The tailor’s muscle because of sitting criss-cross

What muscles are part of the posterior (flexor) compartment of the thigh?

The hamstring muscles:

1. The biceps femoris

2. The semitendinosus

3. The semimembranosus

How many heads does the biceps femoris have? What are they?

2 heads:

1. Long head

2. Short head

What is the popliteal fossa formed by?

The rounded distal tendon of the biceps femoris forms the medial border of the popliteal fossa

What is the pet anserinus?

It is a site of attachment for the sartorius, gracilis, and semi tendinous

Where is the pet anserinus located?

Just deep to the skin at the medial border of the tibial tuberosity

What is the popliteal fossa?

It is a diamond-shaped space on the posterior aspect of the knee bordered laterally by the tendons of the biceps femoris muscle and medially by the tendons of the semitendinosus and semimembranosus muscles

What does the anterior compartment of the leg consist of?

Muscles that dorsiflex the foot… the tibialis anterior, the extensor digitorum, and the extensor hallucis longus

What does the lateral (fibular) compartment of the leg consist of?

2 muscles that plantar flex and evert the foot… the fibularis longus and the fibularis brevis

What is the strongest tendon in th body?

The calcaneal tendon (achilles)

What does the gastrocnemius form?

The prominence of the calf

What is the shape of the soleus?

It is broad and flat

What muscle may be absent in some individuals?

The plantaris

What runs obliquely between the gastrocnemius and the soleus?

The plantaris

What is the plantaris often referred to as?

The freshman’s nerve because first-year medical students sometimes confuse its long slender tendon with the tibial nerve during dissection

What are the superficial muscles of the posterior compartment of the leg?

The triceps surae (gastrocnemius, soleus) and the plantaris

What are the deep muscles of the posterior compartment of the leg?

The popliteus, the tibialis posterior, the flexor digitorum longus, and the flexor hallucis

What shape is the popliteus?

Triangular

What forms the floor of the popliteal fossa?

The popliteus

What muscle is the deepest in the posterior compartment of the leg?

The tibialis posterior

How many divisions does the nervous system contain? What are they?

It contains 2 interconnected divisions:

1. The Central Nervous System (CNS)

2. The Peripheral Nervous System (PNS)

What is the CNS composed of?

The brain and spinal cord

What is the brain enclosed and protected by?

The skull in the cranial cavity

How many neurons does the brain contain?

It contains about 85 billion neurons

What is the spinal cord enclosed and protected by?

The bones of the vertebral column in the vertebral canal

How many neurons does the spinal cord consist of?

About 100 million neurons

What does the CNS do?

It processes many different kinds of incoming sensory information. It is also the source of thoughts, emotions, and memories

Where do most of the nerve impulses that stimulate muscles to contract and glands to secrete originate?

In the CNS

What is the PNS composed of?

All the nervous structures outside the CNS, such as the cranial nerves and their branches, the spinal nerves and their branches, the ganglia, and sensory receptors

What do the structures of the PNS do?

They all link parts of the body to the CNS

What is a nerve?

A bundle of hundreds to thousands of axons plus associated connective tissue and blood vessels that lies outside the brain and spinal cord

What does the median nerve carry?

The median nerve carries signals for motor output and sensory input to and from the muscles and skin of the upper limb

How many pairs of cranial nerves are there?

12 pairs and they emerge from the base of the brain

What do the spinal nerves do?

They each serve a specific region on the right or left side of the body

How many pairs of spinal nerves are there?

31 pairs and they emerge from the spinal cord

What are ganglia?

Clusters of neuron cell bodies outside the CNS

What are sensory receptors?

Structures that monitor changes in the internal and external environment, such as receptors in the skin that detect touch sensations, photoreceptors in the eyes, and olfactory (smell) receptors in the nose

What are the 3 basic functions of the nervous system?

Sensory (input), integrative (control), and motor (output)

What happens during the sensory function?

Sensory receptors detect internal stimuli, such as an increase in blood pressure, and external stimuli, such as a raindrop landing on your arm. Neurons called sensory or afferent neruons carry this sensory information into the brain and spinal cord through the cranial and spinal nerves

What happens during the integrative function?

The nervous system processes sensory information by analyzing and storing some of it and by making decisions for appropriate responses- an activity known as integration

What is an important integrative function?

Perception, which is the conscious awareness of sensory stimuli

Where does perception occur?

In the brain

What are many of the neurons that participate in integration called?

Interneurons, with axons that extend only for a short distance and contact nearby neurons in the brain or spinal cord to set up the complex “circuit boards” of the CNS

What are the vast majority of neurons in the body?

Interneurons and they make up most of the CNS

What happens during the motor function?

Once sensory information is integrated, the nervous system may elicit an appropriate motor response, such as muscular contraction or glandular secretion. The neurons that serve this function are called motor or efferent neurons

What do motor neruons do?

They carry information from the brain toward the spinal cord or out of the brain and spinal cord to effectors through cranial and spinal nerves

What does the stimulaition of the effectors by motor neurons cause?

The muscles to contract and glands to secrete

What do the somatic nerves of the PNS consist of and what do they do?

They consist of sensory neurons called somatic sensory neurons that convey information the the CNS from sensory receptors in the skin, skeletal muscles, and joints, and from the receptors for the special senses

What are the sensory somatic pathways involved in?

They are involved in the input of information to the CNS for integration (processing)

What do the somatic nerves also consist of and what do they do?

They also consist of motor neurons called somatic motor neurons that convey information from the CNS to skeletal muscles only

What are the somatic motor pathways involved in?

The output of information from the CNS that results in a muscular contraction

What do the sensory neurons called autonomic (visceral) sensory neuons do?

They convey information to the CNS from autonomic sensory receptors, located primarily in the visceral organs

What do autonomic motor neurons do?

They convey information from the CNS to smooth muscle, cardiac muscle, and glands and cause the muscles to contract and the glands to secrete

What is the action of the somatic nerves?

It is voluntary

What is the action of the autonomic division of the PNS?

It is involuntary

How many subdivisions are there to the autonomic division and what’re they?

2 divisions-

1. The sympathetic (thoracolumbar) part

2. Parasympathetic (craniospinal) part

What types of actions do the parasympathetic and sympathetic neurons have?

They have opposing actions

In general, what does the sympathetic part help with?

It helps support exercise or emergency actions, so called “fight or flight” responses

What does the parasympathetic part control?

It controls the “rest and digest” activities

What is the major regulator of the smooth muscles of the cardiovascular system?

The sympathetic part of the autonomic division of the PNS

Since the sympathetic part is the major regulator of the smooth muscles of the cardiovascular system, what does it have?

It has a wider distribution, as blood vessels are located everywhere in the body

What is the major regulator of the smooth muscles of the digestive and respiratory systems?

The parasympathetic part of the autonomic division of the PNS

What is the 3rd part of the autonomic division called?

The visceral part (enteric plexuses) also called the “brain of the gut”

How many neurons does the visceral part of the autonomic division contain?

About 100 million neurons that occur throughout most of the length of the digestive canal