Exam 1 Study Guide: Cell Respiration, Autonomic Nervous System, Endocrine System, and Blood

Exam 1 Study Guide

Overview

This study guide covers four major topics essential for understanding foundational concepts in Anatomy & Physiology:

• The Cell & Cellular Respiration

• Autonomic Nervous System (ANS)

• Endocrine System

• Blood

Emphasis is placed on application, critical thinking, and understanding, rather than rote memorization.

Cellular Respiration

Overview of Cellular Respiration

Cellular respiration is the process by which cells convert biochemical energy from nutrients into adenosine triphosphate (ATP), releasing waste products. It includes both aerobic (with oxygen) and anaerobic (without oxygen) pathways.

• Aerobic respiration: Occurs in the presence of oxygen; produces more ATP.

• Anaerobic respiration: Occurs without oxygen; produces less ATP and lactic acid as a byproduct.

Key Steps of Aerobic Respiration

1. Glycolysis: Occurs in the cytoplasm; breaks glucose into pyruvate, yielding 2 ATP.

2. Krebs Cycle (Citric Acid Cycle): Occurs in the mitochondrial matrix; processes pyruvate, producing NADH, FADH2, and 2 ATP.

3. Electron Transport Chain (ETC): Occurs in the inner mitochondrial membrane; uses NADH and FADH2 to generate up to 34 ATP via oxidative phosphorylation.

Overall equation for aerobic respiration:

$\text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \rightarrow 6\text{CO}_2 + 6\text{H}_2\text{O} + \text{ATP}$

• Enzyme function: Enzymes catalyze each step, lowering activation energy.

• Mitochondrial structures: Site of Krebs cycle and ETC.

• ATP yield: Up to 38 ATP per glucose molecule (theoretical maximum).

Example: During intense exercise, muscle cells may switch to anaerobic respiration, producing lactic acid.

Autonomic Nervous System (ANS)

Overview of the ANS

The autonomic nervous system regulates involuntary physiological functions, including heart rate, digestion, respiratory rate, and glandular activity. It is divided into two main branches:

• Sympathetic division: Prepares the body for 'fight or flight' responses.

• Parasympathetic division: Promotes 'rest and digest' activities.

Sympathetic vs. Parasympathetic Pathways

• Sympathetic: Increases heart rate, dilates pupils, inhibits digestion.

• Parasympathetic: Decreases heart rate, constricts pupils, stimulates digestion.

Neurotransmitters and Structures

• Sympathetic neurotransmitter: Norepinephrine (mainly)

• Parasympathetic neurotransmitter: Acetylcholine

• Dual innervation: Most organs receive input from both divisions, allowing fine control.

• Autonomic tone: Baseline level of activity in both divisions.

Example: The heart receives both sympathetic (increases rate) and parasympathetic (decreases rate) input.

Endocrine System

Overview of the Endocrine System

The endocrine system consists of glands that secrete hormones directly into the bloodstream to regulate body functions.

Hormone Transport and Types

• Lipid-soluble hormones: (e.g., steroid hormones) pass through cell membranes; bind to intracellular receptors.

• Water-soluble hormones: (e.g., peptide hormones like insulin) bind to cell surface receptors.

Feedback Loops

• Negative feedback: Most common; hormone release decreases as its effects are achieved (e.g., insulin lowers blood glucose, reducing further insulin release).

• Positive feedback: Less common; hormone release increases in response to a stimulus (e.g., oxytocin during childbirth).

Anterior vs. Posterior Pituitary

• Anterior pituitary: Produces and releases its own hormones (e.g., GH, TSH, ACTH).

• Posterior pituitary: Stores and releases hormones made by the hypothalamus (e.g., ADH, oxytocin).

Example: Insulin (a peptide hormone) is released by the pancreas in response to high blood glucose.

Blood

Overview of Blood

Blood is a connective tissue composed of plasma, red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes). It performs transport, regulatory, and protective functions.

Functions and Components

• Plasma: Liquid matrix; transports nutrients, hormones, waste.

• Erythrocytes: Carry oxygen via hemoglobin.

• Leukocytes: Immune defense; several types with specialized functions.

• Platelets: Involved in blood clotting (hemostasis).

Hematopoiesis

• Hematopoiesis: Formation of blood cells in the bone marrow.

• Erythropoiesis: Production of red blood cells.

• Leukopoiesis: Production of white blood cells.

Leukocyte Types and Functions

• Neutrophils: Phagocytosis of bacteria.

• Lymphocytes: B and T cells; adaptive immunity.

• Monocytes: Become macrophages; phagocytosis.

• Eosinophils: Combat parasites, involved in allergies.

• Basophils: Release histamine; inflammation.

Hemostasis and Blood Typing

• Hemostasis: Process to stop bleeding; involves vascular spasm, platelet plug formation, and coagulation.

• Blood typing: Based on antigens (A, B, AB, O) and Rh factor; important for transfusions.

Example: Type O negative blood is considered the universal donor.

Common Student Pitfalls

• Confusing sympathetic and parasympathetic effects

• Mixing up negative vs. positive feedback

• Not fully understanding how hormones travel and act

• Forgetting blood typing rules (antigen vs. antibody)

What to Prioritize

Topic	High Yield Focus
Cellular Respiration	Steps, energy yield, ETC, oxygen role
ANS	Dual innervation, neurotransmitters, fiber lengths
Endocrine	Feedback loops, hormone transport, major hormone pathways
Blood	WBC functions, hemostasis steps, typing/donation