Comprehensive Biology Study Guide: Integumentary, Skeletal, Muscular, Nervous, and Sensory Systems

Integumentary System

Composed of the skin and its accessory structures.

Protection

A key function of the integumentary system that safeguards underlying structures.

Excretion

The process of eliminating salts, water, and organic waste through the skin.

Thermoregulation

Maintenance of body temperature through mechanisms like blood vessel dilation and sweat secretion.

Detection

The ability to sense touch, pressure, pain, and temperature through the skin.

Production of Vitamin D

A function of the integumentary system that involves synthesizing Vitamin D.

Epidermis

The outer layer of skin composed of keratinized stratified squamous epithelium.

Keratinized Stratified Squamous Epithelium

The type of tissue that makes up the epidermis.

Melanocytes

Cells in the epidermis that produce melanin, affecting skin coloration.

Dermis

The layer of skin made of dense irregular connective tissue containing blood vessels and nerves.

Hypodermis

The layer beneath the dermis, composed mainly of loose connective and fatty tissues.

Accessory Structures

Includes nails, hair, sweat glands, and sebaceous (oil) glands.

Skeletal System

Provides support, protection, attachment points for muscles, mineral and fat storage, and blood cell production.

Bones

Organs made of osseous tissue, connective tissue, blood vessels, lymphatics, and nerves.

Osteoblasts

Cells responsible for laying down new bone.

Osteocytes

Mature bone cells active in mineral recycling.

Osteoclasts

Cells that break down bone matrix for remodeling and mineral regulation.

Ground Substance

Mostly calcium salts, which provide rigidity to bone.

Fibers

Mostly collagen fibers, which provide tensile strength and some flexibility to bone.

Types of Bone Tissue

Includes Compact (Osteon) and Spongy (Trabeculae) bone tissue.

Growth Hormone

Stimulates bone growth throughout childhood.

Estrogen/Testosterone

Hormones that increase the rate of bone growth during puberty and cause growth plate closure.

Nutritional Requirements

Calcium and Phosphate salts are required as constant dietary sources for bone health.

Vitamin D

Necessary for Calcium and Phosphate absorption.

Vitamin C

Required for collagen synthesis.

Vitamin A

Stimulates osteoblast activity (especially collagen production).

Rickets

A condition related to Vitamin A deficiency affecting bone development.

Osteoporosis

A condition related to decreased bone density and increased fracture risk.

Fibrous joints

Joints held together by fibrous connective tissue.

Synovial joints

Joints that have a space or 'synovial cavity' and are surrounded by a joint capsule.

Joint capsule

A structure that surrounds synovial joints.

Synovial membrane

A membrane that lines the synovial cavity and produces synovial fluid.

Synovial fluid

Fluid that lubricates synovial joints.

Hinge joint

A type of synovial joint that allows for movement in one plane.

Ball and socket joint

A type of synovial joint that allows for movement in multiple planes.

Body Movements

Includes Flexion/Extension, Abduction/Adduction, and Circumduction.

Functions of the Muscular System

Produce movement, maintain body posture, stabilize joints, and produce heat.

Skeletal muscle tissue

Striated muscle tissue under voluntary control.

Myofibrils

Structures composed of many sarcomeres end-to-end in muscle fibers.

Sarcomere

The unit of contraction in muscle fibers.

Acetylcholine (ACh)

A neurotransmitter released at the Neuromuscular Junction (NMJ) that initiates muscle contraction.

Action potential

An electrical signal that results from ACh binding and causes muscle contraction.

Calcium ions

Ions released in the cell that cause sarcomeres to shorten, resulting in contraction.

Motor Unit

A unit where the more fibers recruited, the more force is generated; fewer fibers per motor unit means more fine motor control.

Creatine Phosphate

A storage form of energy that is short-lived.

Aerobic Respiration

Requires oxygen, occurs in mitochondria, used for moderate activity, very efficient, and produces carbon dioxide and water as waste.

Anaerobic Respiration

No oxygen needed, used during peak activity, faster but less efficient, produces lactic acid as a waste product.

Muscle Fatigue

Occurs when cells run out of ATP or have an excessive buildup of lactic acid.

Nervous System

The system responsible for communication and control in the body.

Neuroglia

Support, protect, and nourish neurons; provide myelination and outnumber neurons 10 to 1 in the brain.

Neurons

The structural and functional unit of neural tissue; conduct nerve impulses and are amitotic.

Dendrites

Extensions of neurons that receive stimuli.

Axon

A single, long extension of a neuron that conducts impulses away from the cell body.

Nerve impulse

An electrical signal transmitted along a neuron.

Neurotransmitters (NT)

Chemicals released by neurons to communicate with other neurons at a synapse.

Sensory neurons (Afferent neurons)

Carry impulses to the central nervous system (CNS).

Interneurons (Association neurons)

Provide more complex reflexes and associative functions; constitute 99% of all neurons.

Motor neurons (Efferent neurons)

Carry impulses from the CNS to effectors (muscles and glands).

Meninges

Protective membranes that wrap the brain and spinal cord.

Cerebrospinal fluid (CSF)

Fills the spaces between meninges.

Cerebrum

Largest portion; 40% of brain mass; split into hemispheres; outer gray matter is the Cerebral Cortex (convoluted).

Frontal Lobe

Anterior cerebrum; contains voluntary motor areas and prefrontal cortex.

Parietal Lobe

Superior cerebrum; sensory and association areas for somatosensory information and taste.

Temporal Lobe

Lateral cerebrum; sensory and association areas for hearing and olfaction.

Occipital Lobe

Posterior cerebrum; sensory and association areas for vision.

Diencephalon

Interbrain; includes hypothalamus and thalamus.

Hypothalamus

Main autonomic control area, regulates body temperature, hunger, thirst, emotions, and controls the pituitary gland.

Thalamus

Relays sensory information to the cerebral cortex.

Brainstem

Includes Pons and Medulla oblongata; responsible for autonomic nervous regulation.

Medulla oblongata

Contains the cardiovascular center and respiratory center.

Cerebellum

Modifies voluntary motor activity making it smooth, timely, and coordinated; balance and coordination.

Limbic System

Functional grouping responsible for emotional responses and memory.

Spinal Cord

Runs from the skull to the second lumbar vertebra; anchored by meninges and surrounded by CSF.

Reflex actions

Center for many reflex actions (e.g., stretch and urination).

Gray matter

Inner zone of the spinal cord where 'decision making' occurs.

White matter

Outer zone of the spinal cord that conducts information.

Sympathetic Division

Associated with 'fight or flight'; increases heart rate and respiratory rate.

Parasympathetic Division

Associated with 'rest and digest'; decreases heart rate and respiratory rate.

General Senses

Sensors concentrated in the skin including pain, temperature, touch, pressure, vibration, and proprioception.

Vision

Photoreceptor cells in the Retina. 70% of all sensory receptors are in the eyes.

Sclera

White of the eye.

Cornea

Transparent, allows light through.

Iris

Pigmented, changes pupil dimension.

Lens

Focuses image.

Rods

Edges of retina, dim light, peripheral vision, gray tones.

Cones

Center of retina, detailed color vision, requires bright light.

Taste (Gustation)

Chemoreceptors housed in taste buds.

Taste Receptors

Able to detect Sweet, Sour, Bitter, Salty, and Umami.

Smell (Olfaction)

Chemoreceptors on the olfactory membrane on the roof of the nasal cavity.

Olfactory Nerve

Transmits impulses to the cerebral cortex (temporal lobe).

Hearing

Mechanoreceptors in the Cochlea (inner ear).

Auditory Tube

Equalizes pressure between the middle ear and the external environment.

Equilibrium

Mechanoreceptors in the inner ear labyrinth.

Static Equilibrium

Relates to gravity (telling up from down).

Dynamic Equilibrium

Detects movement and the direction of that movement (canals are in all three planes).

Sensory Neuron Density

The area with the shortest average distance between pins is typically the index finger.

Cold Hands Performance

Cold hands perform worse because cold slows the impulse transmission of neurons and stiffens muscles.

Reaction Time (Meter Stick Drop)

Results often show the arms being faster, possibly due to greater strength and ability to grab.

Cancer

Involves mutations that lead to increased cell growth/division, a decrease in repairs, and a decrease in apoptosis.

Mutations

Can result from environmental factors (chemicals, radiation, viruses) or missed due to genetic risk factors (e.g., BRCA 1 or 2).