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Lab 8 Vertebrate Anatomy Muscle and Organs- MAKE SURE TO MAKE A WHOLE SLIDE DEDICATED TO PICTURES

Attachments

  • Tendons: muscle to bone

  • Ligaments: bone to bone

Muscles consist of bundles of bundles

  • Muscle: bundles of fascicles (covered by a layer of connective tissue called epimysium)

  • Fascicle: bundles of muscle fibers (covered by a layer of connective tissue called perimysium)

  • Muscle fiber: bundles of myofibrils (covered by a layer of connective tissue called endomysium)

    • skeletal (striated) muscle fibers consist of myofibrils (which are rows of sarcomeres)

      • this is not the case in smooth muscle, which has thin and thick filaments that don’t arrange into sarcomeres

  • Myofibril: bundles of myofilaments; sarcomere level

  • Myofilament (actin and myosin): interact to generate contraction of sarcomere

Muscle: Basic Histology

  • Sarcomeres: the contractile units of a muscle bundle

  • Sarcomere boundaries are Z disks (aka Z-lines) that hold thin filaments in position

    • in other words, a sarcomere is a region between 2 adjacent z-lines, containing thin actin filaments and thick myosin filaments

    • as a muscle is contracting, you’re bringing the two adjacent z-lines together (Z-disks are pulled together to shorten muscle and contract)

  • The sarcomere’s M-line (middle) holds thick filaments in position

  • Overlapping thick and thin filaments make up the A-band (dark) with the M-line in the center

  • The area of the sarcomeres that only consist of thin filaments makes up the I-band (light) with the Z line in the middle

Muscle Actions (antagonist pairing)

  • Extensors vs Flexors:

    • increase vs decrease joint angle

    • ex: quadriceps extend the knee, while hamstrings flex it

  • Abductors vs Adductors:

    • away from vs toward the body’s midline

    • ex: pectoralis major adducts the arm

  • Retractors vs Protractors:

    • move back vs move forward

  • Supinators vs Pronators:

    • palm/sole anterior vs palm/sole posterior

Muscle Orientation

  • Origin:

    • fixed end of the muscle

    • sometimes difficult to determine (i.e., back muscles)

    • the end closest to the midline of the body

    • Limbs: proximal, trunk: Medial

  • Insertion:

    • portion that causes motion when muscle contracts

    • the end that is furthest from the midline of the body

    • Limbs: distal, trunk: Lateral

Anatomical Orientation

  • Superior vs Inferior

    • closer to the head/upper part of the body vs closer to the feet/away from head

  • Medial vs Lateral

    • toward the midline vs away from the midline of the body

  • Proximal vs Distal

    • toward the origin or trunk of the body vs away from the origin or trunk

  • Superficial vs Deep

    • closer to the body's surface vs away from the body's surface (closer to the body’s interior)

  • Anterior = Ventral vs Posterior = Dorsal

    • the front of the body or structure vs the back

  • Cranial vs Caudal

    • towards the head or skull vs towards the tail end of the body

  • Frontal (coronal) Plane

    • divides the body into a front half and a back half

  • Transverse Plane

    • divides the body into an upper half and lower half

  • Sagittal Plane

    • dividing the body into a left section and a right section

Dorsal/Lateral Aspect Muscles

  • The trapezius is divided into portions name for their different origins:

    • Clavotrapezius

    • Acromiotrapezius

    • Spinotrapezius

  • The trapezius, spinodeltoideus, bicep brachii, latissimus dorsi cross the shoulder joint and move the arm

  • External and internal obliques contain the abdomen

  • Tensor fasciae latae, gluteus maximus, semitendinosus, and biceps femoris cross the hip joint to move the leg

  • Gastrocnemius is the calf muscle that moves the foot

Ventral Aspect Muscles

  • Sternohyoid muscle is used for swallowing

  • Pectoralis major and pectoralis minor are parts of the same muscle with different origins that cross the shoulder joint

  • Linea alba (white line) is connective tissue joining the right and left obliques

Organs

  • Organs are composed of tissues that work together to perform a function

  • The skin is our largest organ and is composed of each tissue type.

  • The nervous system is also composed of all four types, primarily nervous

  • note: in this lab, we are just focusing on the thoracic and abdominal organs

Body Cavities of Rat

  • Thoracic cavity (upper)

  • Abdominal cavity (lower)

Thoracic Organs of Rat

  • Diaphragm separates thoracic and abdominal cavities and sits inferior to lungs

    • Function: primary muscle for breathing (inhalation and exhalation)

    • During inhalation, the diaphragm contracts and moves downward, expanding the thoracic cavity and lowering lung pressure, causing air to flow in

    • During exhalation, the diaphragm relaxes and moves upward, reducing thoracic cavity space and increasing lung pressure, pushing air out

  • Heart is intermediate to the lungs (located between both lungs)

    • Right Atrium – receives deoxygenated blood from the body through veins and sends it to right ventricle

      Right Ventricle – pumps deoxygenated blood to the lungs to pick up oxygen

      Left Atrium – receives oxygenated blood from the lungs

      Left Ventricle – pumps oxygenated blood to the entire body through arteries

    • Myocardium = Heart Muscle

    • Pericardium = Membrane enclosing heart (fluid-filled sac that surrounds and protects the heart)

  • Thymus gland superior to (above) heart

    • Function: immunity – it matures lymphocytes (which is important for fighting infections)

  • The trachea (tube that carries air from the mouth/nose to the lungs) lies anterior to the esophagus (which carries food to the stomach)

    • Epiglottis: a flap that keeps food from entering trachea

    • Lined with cartilaginous rings anteriorly (reinforced to keep it from collapsing when breathing)

    • The trachea bifurcates (splits) at a structure called the carina into bronchial tubes, which enter lungs

      • bronchial tubes lead to bronchioles and then tiny alveoli, where gas exchange occurs → high surface area of the alveoli allows for efficient oxygen intake and CO₂ removal

    • Lungs have lobes – 4 in right lung of rat and 1 in the left lung

Abdominal Organs (located in the coelom- main body cavity)

  • Esophagus (thoracic organ) leads to stomach (carries food to the stomach)

  • The stomach breaks down food, begins protein digestion, and empties into the small intestine through the pyloric sphincter

    • Small intestine is divided into three sections: duodenum to jejunum to ileum, where digestion and absorption of nutrients

    • The pancreas releases digestive enzymes (and secretes insulin and glucagon, which regulate blood sugar levels)

    • The liver produces bile (digestion of fats)

      • Liver is composed of lobes, like the R lung

      • Aside from secreting bile, it also stores glucose as glycogen, filters toxins, and synthesizes macromolecules

      • Blood from the digestive system goes here to get cleaned before traveling back to the heart

  • The ileum passes remnants of food into the colon (large intestine) through the ileocecal sphincter

    • The colon follows this path: cecum → ascending colon → transverse colon → descending colon → rectum → anus, where waste is processed and eliminated

  • The spleen is located posterior and to the left of the stomach, and it filters and stores blood

Organ Coverings

  • Body cavities are lined with membranes that provide protection, lubrication, and support

    • Visceral membrane: lines organs

    • Parietal membrane: lines the cavity wall

  • Thoracic cavity:

    • Heart: covered by the pericardial membrane

    • Lungs: covered by the pleural membrane

  • Abdominal cavity:

    • Peritoneal membrane: lines and protects the abdominal organs

    • Mesentery: connects organs to the body wall (holding them in place)

    • Omentum: connects organ to organ (providing cushioning)


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Lab 8 Vertebrate Anatomy Muscle and Organs- MAKE SURE TO MAKE A WHOLE SLIDE DEDICATED TO PICTURES

Attachments

  • Tendons: muscle to bone

  • Ligaments: bone to bone

Muscles consist of bundles of bundles

  • Muscle: bundles of fascicles (covered by a layer of connective tissue called epimysium)

  • Fascicle: bundles of muscle fibers (covered by a layer of connective tissue called perimysium)

  • Muscle fiber: bundles of myofibrils (covered by a layer of connective tissue called endomysium)

    • skeletal (striated) muscle fibers consist of myofibrils (which are rows of sarcomeres)

      • this is not the case in smooth muscle, which has thin and thick filaments that don’t arrange into sarcomeres

  • Myofibril: bundles of myofilaments; sarcomere level

  • Myofilament (actin and myosin): interact to generate contraction of sarcomere

Muscle: Basic Histology

  • Sarcomeres: the contractile units of a muscle bundle

  • Sarcomere boundaries are Z disks (aka Z-lines) that hold thin filaments in position

    • in other words, a sarcomere is a region between 2 adjacent z-lines, containing thin actin filaments and thick myosin filaments

    • as a muscle is contracting, you’re bringing the two adjacent z-lines together (Z-disks are pulled together to shorten muscle and contract)

  • The sarcomere’s M-line (middle) holds thick filaments in position

  • Overlapping thick and thin filaments make up the A-band (dark) with the M-line in the center

  • The area of the sarcomeres that only consist of thin filaments makes up the I-band (light) with the Z line in the middle

Muscle Actions (antagonist pairing)

  • Extensors vs Flexors:

    • increase vs decrease joint angle

    • ex: quadriceps extend the knee, while hamstrings flex it

  • Abductors vs Adductors:

    • away from vs toward the body’s midline

    • ex: pectoralis major adducts the arm

  • Retractors vs Protractors:

    • move back vs move forward

  • Supinators vs Pronators:

    • palm/sole anterior vs palm/sole posterior

Muscle Orientation

  • Origin:

    • fixed end of the muscle

    • sometimes difficult to determine (i.e., back muscles)

    • the end closest to the midline of the body

    • Limbs: proximal, trunk: Medial

  • Insertion:

    • portion that causes motion when muscle contracts

    • the end that is furthest from the midline of the body

    • Limbs: distal, trunk: Lateral

Anatomical Orientation

  • Superior vs Inferior

    • closer to the head/upper part of the body vs closer to the feet/away from head

  • Medial vs Lateral

    • toward the midline vs away from the midline of the body

  • Proximal vs Distal

    • toward the origin or trunk of the body vs away from the origin or trunk

  • Superficial vs Deep

    • closer to the body's surface vs away from the body's surface (closer to the body’s interior)

  • Anterior = Ventral vs Posterior = Dorsal

    • the front of the body or structure vs the back

  • Cranial vs Caudal

    • towards the head or skull vs towards the tail end of the body

  • Frontal (coronal) Plane

    • divides the body into a front half and a back half

  • Transverse Plane

    • divides the body into an upper half and lower half

  • Sagittal Plane

    • dividing the body into a left section and a right section

Dorsal/Lateral Aspect Muscles

  • The trapezius is divided into portions name for their different origins:

    • Clavotrapezius

    • Acromiotrapezius

    • Spinotrapezius

  • The trapezius, spinodeltoideus, bicep brachii, latissimus dorsi cross the shoulder joint and move the arm

  • External and internal obliques contain the abdomen

  • Tensor fasciae latae, gluteus maximus, semitendinosus, and biceps femoris cross the hip joint to move the leg

  • Gastrocnemius is the calf muscle that moves the foot

Ventral Aspect Muscles

  • Sternohyoid muscle is used for swallowing

  • Pectoralis major and pectoralis minor are parts of the same muscle with different origins that cross the shoulder joint

  • Linea alba (white line) is connective tissue joining the right and left obliques

Organs

  • Organs are composed of tissues that work together to perform a function

  • The skin is our largest organ and is composed of each tissue type.

  • The nervous system is also composed of all four types, primarily nervous

  • note: in this lab, we are just focusing on the thoracic and abdominal organs

Body Cavities of Rat

  • Thoracic cavity (upper)

  • Abdominal cavity (lower)

Thoracic Organs of Rat

  • Diaphragm separates thoracic and abdominal cavities and sits inferior to lungs

    • Function: primary muscle for breathing (inhalation and exhalation)

    • During inhalation, the diaphragm contracts and moves downward, expanding the thoracic cavity and lowering lung pressure, causing air to flow in

    • During exhalation, the diaphragm relaxes and moves upward, reducing thoracic cavity space and increasing lung pressure, pushing air out

  • Heart is intermediate to the lungs (located between both lungs)

    • Right Atrium – receives deoxygenated blood from the body through veins and sends it to right ventricle

      Right Ventricle – pumps deoxygenated blood to the lungs to pick up oxygen

      Left Atrium – receives oxygenated blood from the lungs

      Left Ventricle – pumps oxygenated blood to the entire body through arteries

    • Myocardium = Heart Muscle

    • Pericardium = Membrane enclosing heart (fluid-filled sac that surrounds and protects the heart)

  • Thymus gland superior to (above) heart

    • Function: immunity – it matures lymphocytes (which is important for fighting infections)

  • The trachea (tube that carries air from the mouth/nose to the lungs) lies anterior to the esophagus (which carries food to the stomach)

    • Epiglottis: a flap that keeps food from entering trachea

    • Lined with cartilaginous rings anteriorly (reinforced to keep it from collapsing when breathing)

    • The trachea bifurcates (splits) at a structure called the carina into bronchial tubes, which enter lungs

      • bronchial tubes lead to bronchioles and then tiny alveoli, where gas exchange occurs → high surface area of the alveoli allows for efficient oxygen intake and CO₂ removal

    • Lungs have lobes – 4 in right lung of rat and 1 in the left lung

Abdominal Organs (located in the coelom- main body cavity)

  • Esophagus (thoracic organ) leads to stomach (carries food to the stomach)

  • The stomach breaks down food, begins protein digestion, and empties into the small intestine through the pyloric sphincter

    • Small intestine is divided into three sections: duodenum to jejunum to ileum, where digestion and absorption of nutrients

    • The pancreas releases digestive enzymes (and secretes insulin and glucagon, which regulate blood sugar levels)

    • The liver produces bile (digestion of fats)

      • Liver is composed of lobes, like the R lung

      • Aside from secreting bile, it also stores glucose as glycogen, filters toxins, and synthesizes macromolecules

      • Blood from the digestive system goes here to get cleaned before traveling back to the heart

  • The ileum passes remnants of food into the colon (large intestine) through the ileocecal sphincter

    • The colon follows this path: cecum → ascending colon → transverse colon → descending colon → rectum → anus, where waste is processed and eliminated

  • The spleen is located posterior and to the left of the stomach, and it filters and stores blood

Organ Coverings

  • Body cavities are lined with membranes that provide protection, lubrication, and support

    • Visceral membrane: lines organs

    • Parietal membrane: lines the cavity wall

  • Thoracic cavity:

    • Heart: covered by the pericardial membrane

    • Lungs: covered by the pleural membrane

  • Abdominal cavity:

    • Peritoneal membrane: lines and protects the abdominal organs

    • Mesentery: connects organs to the body wall (holding them in place)

    • Omentum: connects organ to organ (providing cushioning)