Test 3 Flashcards
Body systems
What are the main divisions of the nervous system?
Central nervous system (CNS) and Peripheral nervous system (PNS)
The CNS includes the brain and spinal cord, while the PNS includes all nerves.
What are the three main parts of a neuron?
Cell body, dendrites, axon
Dendrites conduct impulses to the cell body, while the axon conducts impulses away.
What type of neuron conducts impulses to the spinal cord and brain?
Sensory (afferent) neurons
What type of neuron conducts impulses away from the brain and spinal cord?
Motor (efferent) neurons
What are interneurons also known as?
Central or connecting neurons
What are the three main types of glial cells in the CNS?
Astrocytes, microglia, oligodendrocytes
What is the function of astrocytes?
Anchor small blood vessels to neurons
What is the role of microglia?
Carry out phagocytosis in inflamed brain tissue
What do oligodendrocytes form on axons in the CNS?
Myelin sheaths
What is the difference between a nerve and a tract?
A nerve is a bundle of peripheral axons; a tract is a bundle of central axons.
What tissues primarily compose white matter?
Myelinated axons
What tissues primarily compose gray matter?
Cell bodies and unmyelinated fibers
What is the simplest form of a reflex arc?
A two-neuron arc consisting of sensory neurons and motor neurons
What is a three-neuron arc in a reflex arc?
Sensory neurons synapsing with interneurons that synapse with motor neurons
What initiates a nerve impulse?
Inward movement of Na+ depolarizes the membrane
What are neurotransmitters?
Chemicals by which neurons communicate
Name two types of autonomic nervous system divisions.
Sympathetic and parasympathetic systems
What is the main function of the sympathetic division?
Controls visceral effectors during emergency or stress situations
What is the fight-or-flight response?
Group of changes induced by sympathetic control during stress
Where are parasympathetic preganglionic neurons located?
In the gray matter of the brainstem and sacral segments of the spinal cord
What neurotransmitter is released by cholinergic fibers?
Acetylcholine
What neurotransmitter is primarily released by adrenergic fibers?
Norepinephrine (noradrenaline)
Fill in the blank: The __________ system regulates the body’s automatic functions.
Autonomic nervous system
True or False: The autonomic nervous system maintains homeostasis.
True
What part of the brain acts as the major center for controlling the autonomic nervous system?
Hypothalamus
What is the primary function of the thalamus?
Relays sensory impulses to the cerebral cortex
What is the largest part of the human brain?
Cerebrum
What regulates automatic movements and posture?
Basal nuclei
What are the main components of a reflex arc?
Receptors, sensory neurons, interneurons, motor neurons, effectors
What are the three types of muscle tissue in the body?
Skeletal muscle, Cardiac muscle, Smooth muscle
Skeletal muscle is voluntary, cardiac muscle is involuntary and found in the heart, while smooth muscle is also involuntary and found in walls of hollow organs.
What is the primary function of muscle fibers?
Contraction (shortening)
Muscle fibers enable movement by contracting and pulling on bones.
What is the basic functional unit of skeletal muscle?
Sarcomere
Sarcomeres are the repeating units within muscle fibers where contraction occurs.
What is the role of calcium and ATP in muscle contraction?
Contraction requires calcium and ATP
Calcium ions facilitate the interaction between myofilaments, while ATP provides the energy needed for contraction.
What is a motor unit?
Combination of a motor neuron with the muscle fibers it controls
Motor units are essential for muscle contraction as they transmit nerve impulses to muscle fibers.
Define ‘prime mover’ in muscle function.
Mainly responsible for producing a given movement
Prime movers work alongside synergist and antagonist muscles to facilitate movement.
Fill in the blank: A continuous, low-strength muscle contraction called _______ enables us to maintain body position.
tonic contraction
Tonic contraction helps maintain posture without producing noticeable movement.
What causes muscle fatigue?
Reduced strength of muscle contraction due to repeated stimulation without adequate rest
Muscle fatigue can lead to lactic acid buildup, contributing to soreness.
True or False: Isometric contractions produce movement.
False
Isometric contractions increase tension without shortening the muscle, thus not producing movement.
List the types of muscle contractions.
- Twitch contractions
- Tetanic contractions
- Isotonic contractions
- Isometric contractions
Each type of contraction serves different functional roles in muscle activity.
What are the effects of regular exercise on skeletal muscle?
- Improves muscle tone and posture
- Increases muscle size (hypertrophy)
- Enhances heart and lung function
- Reduces fatigue
Regular exercise adapts muscles to handle more workload effectively.
What is oxygen debt?
Metabolic effort required to burn excess lactic acid during exercise
Oxygen debt is compensated by labored breathing after strenuous activity.
What are the major movements produced by skeletal muscle contractions?
- Flexion
- Extension
- Abduction
- Adduction
- Rotation
- Circumduction
These movements are essential for various physical activities and body mechanics.
What is the role of connective tissue in skeletal muscles?
Forms wrappers around muscle fibers and groups, and attaches muscles to bones via tendons
Connective tissue supports and protects muscle structures.
What is the difference between concentric and eccentric contractions?
- Concentric: Muscle shortens to move toward origin
- Eccentric: Muscle lengthens under tension
Both types of contractions are crucial for different movements in daily activities.
What are the muscles of the upper extremities?
- Pectoralis major
- Latissimus dorsi
- Deltoid
- Biceps brachii
- Triceps brachii
These muscles are primarily responsible for arm movements.
What is the function of the diaphragm?
Muscle involved in respiration
The diaphragm contracts to increase thoracic cavity volume, facilitating breathing.
What are the functions of bones?
Supports and gives shape to the body, protects internal organs, helps make movements possible, stores calcium
Hormones regulate calcium storage, with calcitonin increasing storage and parathyroid hormone reducing it.
What is hemopoiesis?
Blood cell formation in red bone marrow
What are the four major bone types according to overall shape?
- Long bones
- Short bones
- Flat bones
- Irregular bones
Some scientists also recognize a sesamoid (round) bone category.
Give an example of a long bone.
Humerus (arm)
Give an example of a short bone.
Carpals (wrist)
Give an example of a flat bone.
Frontal (skull)
Give an example of an irregular bone.
Vertebrae (spinal cord)
What is the diaphysis of a long bone?
Hollow tube of hard compact bone
What is found inside the medullary cavity of long bones?
Yellow bone marrow
What is the function of articular cartilage?
Covers epiphyses and functions as a cushion
What is the periosteum?
Strong membrane covering bone everywhere except at joint surfaces
What is the endosteum?
Membrane lining medullary cavity
What is the structure of flat bones?
Spongy bone layer sandwiched between two compact bone layers
This spongy bone layer is referred to as diploe.
What is the microscopic structure of cancellous bone?
Texture results from needlelike threads of bone called trabecular surrounded by a network of open spaces
What are osteocytes?
Bone cells found inside spaces called lacunae
What is the matrix of cartilage tissue like?
Gel-like and lacks blood vessels
What are osteoblasts?
Cells that form new bone
What does ossification refer to?
The process by which baby bones fuse together
What is the axial skeleton composed of?
80 bones including skull bones, ear bones, face bones, spine, thorax, and hyoid bone
How many bones are in the human skull?
22 bones
What is the mnemonic for the facial bones?
My mandible chews nine very large zucchini pizzas
How many cervical vertebrae are there?
7
What are the types of joints?
- Diarthroses (free movement)
- Synarthroses (no movement)
- Amphiarthroses (slight movement)
What is a diarthrotic joint?
A joint that allows free movement
What is the radius’s position in relation to the thumb?
On the thumb side
Fill in the blank: The fibula is ______.
far (distal)
What is found between joints?
Synovial fluid and cartilage
