Biol 205 Fall 2020 Exam 3 Study Guide PDF

**Exam 3 Study Guide** **Biol 205 Fall 2020** **MUSCLE TISSUE** - - - - - - - - - - **SKELETAL MUSCLE TISSUE** - What are some important functions of muscle tissue. How does it perform those functions? **The structure of skeletal muscle** Be able to describe t...

**Exam 3 Study Guide** **Biol 205 Fall 2020** **MUSCLE TISSUE** - - - - - - - - - - **SKELETAL MUSCLE TISSUE** - What are some important functions of muscle tissue. How does it perform those functions? **The structure of skeletal muscle** Be able to describe the gross structure of a skeletal muscle. Understanding how skeletal muscles function, requires that you understand the interaction of various tissues and cellular components. *The first step to making these connections is to understand these organizational schemes.* - Know these structures and how they are organized: - Epimysium - Perimysium, - Endomysium, - Fascicles - muscle fibers - myofibrils - myofilaments. - **The structure of a skeletal muscle fiber (cell)** - Be able to go down a level from the **endomysium** and understand how a skeletal muscle cell is organized. - Identify each of these structures in the diagram below and be able to describe their functions - Sarcolemma - Triad - Transverse tubule - Terminal cisternae of Sarcoplasmic Reticulum - Myofibrils muscle cell *Muscle fibers contain bundles of myofibrils. Myofibrils are composed of smaller protein filaments (myofilaments). You should be able to describe how these proteins work together.* - Identify each of these structures in the diagram below and what their function is.  **THE SLIDING FILAMENT MODEL and its triggers** - Starting from the Synapse: - What causes the release of acetylcholine (Ach)? - Can you trace this all the way back to a graded potential in a motor neuron? - What is the critical role of Ca^2+^ ? - Is the motor neuron a pre- or post-synaptic cell? - Does Ach cause in inhibitory or an excitatory post synaptic potential? - Is the muscle cell a pre- or post-synaptic cell? - What is unique about the **motor end plate** of the **neuromuscular junction**? - Review Action Potentials. Understanding these is critical to understanding how the filaments are triggered to interact with one another. - How does an action potential (AP) travel along a skeletal muscle cell and how is this different from the way it travels along a neuron? - What causes the release of Ca^2+^ ? - What is the role of Ca^2+^ here? How is it different from its role at the synapse? - Filament interactions. - Be able to explain (or better yet draw) how the interaction between **actin**, **myosin**, **tropomyosin** and **troponin** interact to produce muscular contractions. - The figure below shows the interactions between actin and myosin. Fill it out and add the roles of troponin and tropomyosin to the figure. Cross\_bridge **THE SARCOMERE AND THE DEVELOPMENT OF MUSCLE TENSION** - How do the interactions between actin and myosin affect sarcomere length? - How does sarcomere length affect the amount of tension that a myofibril can produce? - How does that affect the tension that the whole cell or the whole muscle can produce? - Can you think of situations when your sarcomere length might not be optimal? \*These happen every day. - What is a **twitch**? - Define these elements of a **myogram**: - Latent period - Contraction Phase - Relaxation Phase **ENERGY FOR WORKING MUSCLES** - Under which conditions are muscles most likely to be powered by: - Creatine Phosphate - Aerobic metabolism - Glycolysis alone (anaerobic metabolism) **THE ROLES OF DIFFERENT MUSCLE FIBER TYPES** - Be able to compare and contrast the three different fiber types. - What are the costs and benefits of having each type? **THE BRAIN (CH13):** **PROTECTION OF THE BRAIN AND SPINAL CORD:** - - - - - - - - **CEREBROSPINAL FLUID (CSF)** - - - - - - - What is it made from? How is used up CSF dealt with? **ORGANIZATION OF NEURONS IN THE BRAIN:** - How does the distribution of white and gray matter in the spinal cord and brain differ? - Why is that and what does that have to do with information processing and transfer? **MAJOR PARTS OF THE BRAIN** - - - **Midbrain** - What are the major functions controlled by the midbrain? - The midbrain is a major information highway between the spinal cord, pons and medulla to the cerebrum via the **cerebral peduncles.** - It also controls many reflex actions of the head, neck and eyes via the **corpora quadrigemina** - How do these reflexes work? - **Pons** - What are the major functions controlled by the pons? - How do the pons and the cerebellum work together? How are their functions important and how do they relate to the vestibulocochlear nerve? - **Medulla Oblongata** - What are the major functions controlled by the medulla? - - - - - **Thalamus** - Has many nuclei (What is a "**nucleus"** in the CNS?) involved in various functions. What is the significance of having so many sensory and motor "relay" centers? - In what directions are the motor and sensory information moving? - What is the relationship between the thalamus and the cerebellum? - **Hypothalamus** - Like the thalamus, this region also has many nuclei. What homeostatic controls are located in this area? - Why is this structure often considered "the boss" of the ANS? - What is the relationship between the hypothalamus and the **pituitary gland**? - **Pineal gland** - What is its function? - - - **STRUCTURE OF THE SPINAL CORD (CH 13)** - Define - Gray matter - White Matter - What parts of a neuron do they represent? - **Be able to detail the flow of motor, fine touch/proprioception, and pain and temperature information through the spinal cord and brain.** - **Where do they decussate?** - **Where in the spinal cord do they travel?** - What are the three meningeal layers? - **Describe the direction of information flow into and out of the spinal column. What structures are involved? Where are the axons, dendrites, cell bodies of the involved cells located? Maybe draw a picture?** - **Why are dermatome maps useful?** - How does the manner in which the gray and white matter are organized affect information flow? - How can one spinal nerve carry both motor and sensory information? - Differentiate between Sensory (Afferent) and Motor (Efferent) pathways and what information (sensory and/ or motor) that carries. - **Reflexes and Reflex Arcs** - What are the general components of a reflex arc? - What are **innate** and **acquired** reflexes? - Which one is more likely to be monosynaptic or polysynaptic? - Can you come up with examples of each? - What does it mean when reflex arcs are mono or polysynaptic (see above)? - Examine the patellar tendon reflex in detail. - Why are inhibition AND stimulation components of the reflex response? - How is this related to the fact that the arc is polysynaptic? - If you knew that the stimulus (hammer) was coming, you could override the reflex and not allow your leg to kick. How can you do that?