Human Nervous System: Brain, Senses, and Memory
The Human Nervous System: Structure and Function
1.1 The Nerve Pathway
The four elements of a simple nerve pathway are:
- Receptor: Detects a stimulus.
- Sensory Neuron: Transmits the signal to the central nervous system.
- Integration Center: (Usually the spinal cord or brain) Processes the signal.
- Motor Neuron: Transmits a signal to an effector.
- Effector: Carries out response.
1.2 The Spinal Cord
The spinal cord contains different types of neurons. If the spinal cord is severed, the body becomes paralyzed below
Read MoreUnderstanding the Dark Phase of Photosynthesis: Carbon Fixation
The Dark Phase of Photosynthesis: Carbon Fixation
Plant cells contain the enzymes necessary to reduce and assimilate nutrients, transforming them into biomolecules within living matter. The dark phase involves the transformation of carbon, nitrogen, and sulfur compounds that can be incorporated into anabolic pathways.
Carbon Fixation
The photosynthetic fixation of CO2 occurs in the stroma of the chloroplasts via the Calvin-Benson cycle. This cycle leads to the incorporation of CO2 to form organic compounds
Read MoreUnderstanding Human Biology: Cell Structure to Ecosystem Impacts
Cell Structure and Human Biology
Cell Structure
Plasma membrane, cytoplasm (ribosomes, mitochondria, endoplasmic reticulum, Golgi apparatus, vacuoles, lysosomes), nucleus (nuclear membrane, nucleoplasm, chromatin, nucleolus).
Tissues
- Epithelial: Lining epithelium (mucous membranes, endothelia, epidermis), gland (exocrine, endocrine, mixed)
- Connective: Connective tissue, adipose, cartilaginous, osseous
- Muscle: Smooth, striated, cardiac
- Nerves: Neurons, glial cells
Body Organization
Structures formed by various
Read MoreEcosystem Energy Flow, Nutrient Cycles, and Plant Responses
Food: Contains energy and nutrients required for maintenance/survival, growth/development, and reproduction.
Carbon:
- Auto (from CO2, inorganic)
- Hetero (from organic molecules)
Energy:
- Photo (from light)
- Chemo (oxidizing inorganic or organic molecules)
Organisms:
- Prokaryotes: Have all carbon and energy types.
- Protists: Photoautotrophs and chemoheterotrophs.
- Plants: Photoautotrophs and chemoheterotrophs.
- Fungi and Animals: Chemoheterotrophs.
Food Chains: Show how energy & nutrients move between organisms.
Read MoreCommon Diseases: Etiology, Symptoms, and Management
Urinary Tract Infections
Etiopathogenesis: It depends on several factors, including host factors, bacterial virulence factors, and anatomical and physiological factors. Host factors— Factors that impair the immune response, such as immunosuppressive medications, HIV infection, or diabetes, can increase the risk of UTI. In addition, female anatomy (shorter urethra and closer proximity of urethral opening to the anus) makes women more prone to UTIs.
Clinical manifestations:
- A strong, persistent urge
Understanding Allergy, Immunity, and Genetics
Allergy and Immune Response
Allergy
Anti-allergen interacts with mast cells, leading to histamine production and other cellular blood circulation effects.
Humoral Response
B lymphocytes produce antibodies (AC) that bind to antigens. AC functions include:
- Neutralizing antigens
- Agglutination
- Precipitation
- Activation of the complement system (a group of inactive proteins in plasma)
Cellular Response
Macrophages present antigens on their surface along with Major Histocompatibility Complex (MHC) proteins. This
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