BIO 305 EXAM 4 2026 REVISION NOTES AND
STRUCTURED BIOLOGICAL SYSTEMS
OVERVIEW GUIDE
◉ What hypothalamic hormone inhibits prolactin? Answer: DA or
PIH (dopamine or prolactin inhibiting hormone)
◉ What does CRH cause the release of in the anterior pituitary?
Answer: ACTH
◉ What's important about the multiple step cascades found in the
endocrine system? Answer: Slows responses, provides opportunities
for regulation, neural integration, and signal amplification
◉ What are the three types of muscle, and which ones are striated?
Answer: Skeletal (striated), cardiac (striated), and smooth (non
striated)
◉ (------) muscle cells are formed by the fusion of many progenitor
cells, forming an elongated, multinucleated cell. Answer: Skeletal
,◉ What is the difference between muscle fibers and fibrils? Answer:
Fibers are another term for the cell while fibrils are filaments within
the cell
◉ What kind of connective tissue binds muscles to bone? Answer:
Tendons
◉ What are the three distinctive structures of skeletal muscles?
Answer: Sarcoplasmic reticulum, myofibrils, and a lot of
mitochondria
◉ What organelle is sarcoplasmic recticulum a specialized form of?
Answer: Endoplasmic recticulum
◉ What surrounds myofibrils? Answer: The sarcoplasmic recticulum
◉ What's the importance of the sarcoplasmic recticulum being close
to T tubules? Answer: Allows action potentials to reach interior of
cells
◉ What makes up the majority of skeletal cell volume? Answer:
Myofibrils
, ◉ What gives the skeletal cell its striated appearance? Answer:
Myofibrils
◉ What is the functional unit of the muscle cell called? Answer:
Sarcomere
◉ What binds the Sarcomere? Answer: Z lines/discs (see diagram)
◉ What are the filaments that extend from the z line called? Answer:
Actin (thin filaments)
◉ What do myosin filaments extend from? Answer: M line
◉ What type(s) of filaments are found in a sarcomere's I band?
Answer: Actin
◉ What anchors myosin? Answer: Titin
◉ What type(s) of filaments are found in a sarcomere's a band
Answer: Actin and myosin
◉ What type(s) of filaments are found in a sarcomere's H zone?
Answer: Myosin
STRUCTURED BIOLOGICAL SYSTEMS
OVERVIEW GUIDE
◉ What hypothalamic hormone inhibits prolactin? Answer: DA or
PIH (dopamine or prolactin inhibiting hormone)
◉ What does CRH cause the release of in the anterior pituitary?
Answer: ACTH
◉ What's important about the multiple step cascades found in the
endocrine system? Answer: Slows responses, provides opportunities
for regulation, neural integration, and signal amplification
◉ What are the three types of muscle, and which ones are striated?
Answer: Skeletal (striated), cardiac (striated), and smooth (non
striated)
◉ (------) muscle cells are formed by the fusion of many progenitor
cells, forming an elongated, multinucleated cell. Answer: Skeletal
,◉ What is the difference between muscle fibers and fibrils? Answer:
Fibers are another term for the cell while fibrils are filaments within
the cell
◉ What kind of connective tissue binds muscles to bone? Answer:
Tendons
◉ What are the three distinctive structures of skeletal muscles?
Answer: Sarcoplasmic reticulum, myofibrils, and a lot of
mitochondria
◉ What organelle is sarcoplasmic recticulum a specialized form of?
Answer: Endoplasmic recticulum
◉ What surrounds myofibrils? Answer: The sarcoplasmic recticulum
◉ What's the importance of the sarcoplasmic recticulum being close
to T tubules? Answer: Allows action potentials to reach interior of
cells
◉ What makes up the majority of skeletal cell volume? Answer:
Myofibrils
, ◉ What gives the skeletal cell its striated appearance? Answer:
Myofibrils
◉ What is the functional unit of the muscle cell called? Answer:
Sarcomere
◉ What binds the Sarcomere? Answer: Z lines/discs (see diagram)
◉ What are the filaments that extend from the z line called? Answer:
Actin (thin filaments)
◉ What do myosin filaments extend from? Answer: M line
◉ What type(s) of filaments are found in a sarcomere's I band?
Answer: Actin
◉ What anchors myosin? Answer: Titin
◉ What type(s) of filaments are found in a sarcomere's a band
Answer: Actin and myosin
◉ What type(s) of filaments are found in a sarcomere's H zone?
Answer: Myosin
