Biology 235 - Exam 3 Questions With Verified
Answers 2024/2025
What do golgi tendon organs do?
- detect changes in muscle tension
- when the muscle contracts, the Golgi tendon organ is stimulated, and it sends a signal to the brain to
relax the muscle
what do spindle muscle cells do?
- detect changes in the length of a muscle
- if it senses the muscle is lengthening, it sends a signal to contract. if it continues to lengthen, they
will eventually stop the signals and the muscle will relax
stretch spinal reflex
monosynaptic reflex that regulates muscle length through neuronal stimulation
- contracts a muscle that is being stretched
what type of afferent neuron is involved in the spinal reflex
1a sensory afferent neuron
why does lactate form from activity of glycolytic muscle cells?
Glycolytic (Type 2b) muscle cells produce lactate as a by-product
how can lactate be used by other cells
Lactate IS FUEL. It leaves muscle, enters blood and is used elsewhere for ATP production (using O2)
what is the myth regarding lactate/lactic acid?
This lactate is not the cause of muscle fatigue and soreness. Earlier, it was thought that lactate turned
acidic (lactic acid)
what is the function of creatine phosphate at muscles?
Rapid release reserve of high-energy. It's used in muscle cells to store energy for sprinting and
explosive exercise.
how are single and multiunit smooth muscle's innervation different?
smooth
- the autonomic nervous system innervates a single cell
multiunit
- densely innervated by autonomic nerve fibers
how do gap junctions help single unit smooth muscles coordinate their contraction?
synchronizes membrane depolarization and contractions so the muscle contracts as a single unit
, can you give an example of single unit or multiunit smooth muscle?
single unit
- uterus, intestine, bladde
multiunit
- iris of the eye and arrector pili muscles in the skin
which muscle type is more similar to how skeletal muscles are triggered to contract?
multiunit
Artioventricular valves
mitral (bicuspid)
- located between the left atrium and ventricle
tricuspid
- valve between right atrium and ventricle
aortic valve
The semilunar valve separating the aorta from the left ventricle that prevents blood from flowing back
into the left ventricle.
pulmonary valve
valve positioned between the right ventricle and the pulmonary artery
chordae tendineae
thin bands of fibrous tissue that attach to the valves in the heart and prevent them from inverting
intercalated discs
support synchronized contraction of cardiac tissue
what junctions are at an intercalated disc?
The junctions are Desmosomes (to keep cells from separating) and Gap junctions (allows APs to
propagate).
basic flow through the heart
- Atrial and Ventricular diastole fills the ventricles with blood
- Sinoatrial (SA) node starts systole, starting the contraction of the atrium.
- electrical signal goes to the Atrioventricular (AV) node where the electrical signal experiences a little
bit of a delay allowing the final bit of blood to fill the ventricles
- the signal goes to the bundle of His then to the purkinje fibers allowing a squeezing action of the
ventricles to push as much blood as possible out of the heart.
which side pumps to systemic vs pulmonary circuits?
left ventricle pumps for the systemic circuit which provides blood supply to the tissue cells
Answers 2024/2025
What do golgi tendon organs do?
- detect changes in muscle tension
- when the muscle contracts, the Golgi tendon organ is stimulated, and it sends a signal to the brain to
relax the muscle
what do spindle muscle cells do?
- detect changes in the length of a muscle
- if it senses the muscle is lengthening, it sends a signal to contract. if it continues to lengthen, they
will eventually stop the signals and the muscle will relax
stretch spinal reflex
monosynaptic reflex that regulates muscle length through neuronal stimulation
- contracts a muscle that is being stretched
what type of afferent neuron is involved in the spinal reflex
1a sensory afferent neuron
why does lactate form from activity of glycolytic muscle cells?
Glycolytic (Type 2b) muscle cells produce lactate as a by-product
how can lactate be used by other cells
Lactate IS FUEL. It leaves muscle, enters blood and is used elsewhere for ATP production (using O2)
what is the myth regarding lactate/lactic acid?
This lactate is not the cause of muscle fatigue and soreness. Earlier, it was thought that lactate turned
acidic (lactic acid)
what is the function of creatine phosphate at muscles?
Rapid release reserve of high-energy. It's used in muscle cells to store energy for sprinting and
explosive exercise.
how are single and multiunit smooth muscle's innervation different?
smooth
- the autonomic nervous system innervates a single cell
multiunit
- densely innervated by autonomic nerve fibers
how do gap junctions help single unit smooth muscles coordinate their contraction?
synchronizes membrane depolarization and contractions so the muscle contracts as a single unit
, can you give an example of single unit or multiunit smooth muscle?
single unit
- uterus, intestine, bladde
multiunit
- iris of the eye and arrector pili muscles in the skin
which muscle type is more similar to how skeletal muscles are triggered to contract?
multiunit
Artioventricular valves
mitral (bicuspid)
- located between the left atrium and ventricle
tricuspid
- valve between right atrium and ventricle
aortic valve
The semilunar valve separating the aorta from the left ventricle that prevents blood from flowing back
into the left ventricle.
pulmonary valve
valve positioned between the right ventricle and the pulmonary artery
chordae tendineae
thin bands of fibrous tissue that attach to the valves in the heart and prevent them from inverting
intercalated discs
support synchronized contraction of cardiac tissue
what junctions are at an intercalated disc?
The junctions are Desmosomes (to keep cells from separating) and Gap junctions (allows APs to
propagate).
basic flow through the heart
- Atrial and Ventricular diastole fills the ventricles with blood
- Sinoatrial (SA) node starts systole, starting the contraction of the atrium.
- electrical signal goes to the Atrioventricular (AV) node where the electrical signal experiences a little
bit of a delay allowing the final bit of blood to fill the ventricles
- the signal goes to the bundle of His then to the purkinje fibers allowing a squeezing action of the
ventricles to push as much blood as possible out of the heart.
which side pumps to systemic vs pulmonary circuits?
left ventricle pumps for the systemic circuit which provides blood supply to the tissue cells
